How the Coolhaus Founder Stayed Chill as One Food Truck Became a Frozen Treat Empire Coolhaus founder Natasha Case went from selling ice cream sandwiches out of an old postal truck to self-made millionaire. Here's how.

In 2009, Natasha Case and Freya Estrella were selling ice cream sandwiches out of a beat up postal van they bought on Craigslist. With background in the design and real estate fields, they spiced up the classic frozen treat by naming their ice cream sandwiches after architects and architectural movements that inspired them, like the peanut butter ice cream between double chocolate cookies called I. M. Pei-nutbutter.

Today, Coolhaus is much more than an architecturally savvy food truck. Coolhaus now sells treats in over 1,500 gourmet markets across the nation. Through partnerships with Urban Outfitters and Quicksilver, you can find Coolhaus prepackaged treats while you're shopping for clothes. Soon, you'll even be able to make your own Coolhaus sandwiches, with a cookbook coming out in May.

Entrepreneur.com was able to ask co-founder Natasha Case a few questions about expansion, partnerships and the delicious and evolving food truck industry. Check out how she's managed to grow and transform her business. (And don't miss the exclusive recipe she gave us from the Coolhaus Ice Cream Book.)

Related: How Chicken Soup For the Soul Started Selling Actual Soup

How has Coolhaus gone from a single food truck to a huge brand with carts and trucks across the country, a line of prepackaged frozen goodies and a soon-to-be-released cookbook?

By creating a brand and a vision that is beyond just a single product or market approach. Because Coolhaus, as a concept, has a culture and a story that really resonates with an audience, we can do anything. This also creates buy-in internally: if the Coolhaus team/staff are part of our vision beyond the day-to-day operations, they will be inspired to help take the brand to the next level. You always need that level of motivation amongst your team to make a company successful and scalable.

What have been the major challenges of Coolhaus's expansion?

Deciding which components of the business to focus on (ie trucks, stores or wholesale distribution) and building strategy around that, cash-flowing through the off-season (both in terms of managing huge production runs for grocery orders and maintaining payroll for salaried staff), and managing people. It can be challenging in the service industry, because many staff members have other passions (ie music, modeling, art, comedy), which creates a wonderful environment, but can bring other challenges in terms of maintaining the team.

How has your architecture background played a role in Coolhaus?

It has been a massive help: architecture is a great background for creating a brand identity and using visuals to tell a story. Architecture is also client/project driven, just like the service side of our business. Also, my technical design skills and training have helped with packaging design, web design, and creating many other marketing collaterals. It has also allowed us to fold-in a whole other audience to our brand: we have a tremendous following amongst the food/ice cream loving community AND the design community. How many dessert companies can say the same?

What prompted Coolhaus to decide to start selling treats in stores, and how were markets such as Urban Outfitters and Quicksilver selected?

I love the idea of getting the best possible product into as many hands as possible: grocery distribution allows us to do that! It's just so scalable: while I love that any Angeleno can come to our carts, stores and trucks, for example (or anyone in Austin, Dallas and New York City for that matter), at the end of the day, that's only a fragment of the country. Now with our retail partners (ie Whole Foods, Sprouts, Fresh Direct, Gelson's, Safeway, and Earth Fare, to name a few) people in basically every state (and even Guam, the Caribbean and Puerto Rico!) can have Coolhaus. The scalability is also just a great business model; we've had one person essentially managing the distribution from 20 to 2,000 stores. So, you grow the revenue tremendously without necessarily increasing overhead.

As far as Urban Outfitters and Quiksilver, at Coolhaus we love to think of alternative retailers that could sell our products. As long as there is a freezer and a plug, Coolhaus can be anywhere! So, we found a great fit with these fashion companies that usher in our clientele, and we provide a great way for them to compete with online retailers---no matter how fast and easy online shopping can be, you can never have the experience of eating a Coolhaus ice cream sandwich, bar or pint while you shop online!

Related: Why Dairy Queen Is Finally Opening Up in Manhattan

How has the food truck industry evolved since you founded Coolhaus in 2009? What do you think is next for food trucks?

Tremendously. I think people now see the truck as a piece of a broader strategy: a truck is a great marketing tool for building brand awareness and doing alternative services like providing catering or corporate activations. You have to have a vision beyond a single truck to make it all work.

What sets Coolhaus apart from other food trucks?

We have a tri-fold approach on the marketplace: trucks, brick and mortar AND wholesale distribution. I haven't seen any truck grow with grocery stores, movie theaters, stadiums, fashion retailers, etc. the way we have. You can't really package most of what you can buy from trucks, so we have that advantage! Also, the architecture component is a huge edge for us: we do so much of our design in-house, which gives it an authentic feel and a truer association. Plus, we have the eyes and ears of the design world---most "food trucks' can't say that.

What advice do you have for other entrepreneurs in the food industry?

Think about your food concept beyond what it means as a passionate hobby---is it a viable, scalable business, and where do you see it going in the short and long-term.

What's next for you and Coolhaus?

Our Coolhaus Ice Cream Book (May 20th HMH Publishing) that gives away all of our secrets. Continue to increase sales in the channels with have by adding our new products (hand-dipped ice cream bars on sticks and hand-packed pints), and add additional retail (i.e. - add more Whole Foods, more stadiums, more alternative retailers), and we are working on an international deal right now as well!

Related: A New Kind of Trailer Park: Entrepreneurs Create Community for Mobile Businesses

Case offered up an exclusive look at one of the recipes from her book. Check it out:

Nutella Toasted Almond Ice Cream

Makes about: 11⁄2 quarts | Active time: 50 to 55 minutes

Toasted almonds give an extra twist to the hazelnut essence of this ice cream.

3⁄4 cup hazelnuts

2 cups whole milk

2 cups heavy cream

1 1⁄4 cups granulated sugar

8 large egg yolks

1⁄2 cup sliced almonds (with skins)

Maldon sea salt, for sprinkling

1. Preheat oven to 325 degrees.

2. Spread hazelnuts in a single layer on a baking sheet. Toast in oven for 5 to 10 minutes, or until fragrant and golden. Remove from oven and let cool. Smash into pieces.

3. In a 4-quart saucepan, combine milk, cream, and half of sugar and bring to a boil over medium-high heat. Meanwhile, beat yolks and remaining sugar until smooth, heavy, and pale yellow, about 30 seconds.

4. When cream mixture boils, add toasted hazelnuts, remove from heat, and let stand for 10 minutes. Strain cream mixture through a fine-mesh sieve into a bowl. Transfer hazelnuts to a blender and puree, adding a bit of cream mixture to help pureeing process.

5. Strain pureed hazelnuts through a fine-mesh sieve into bowl with remaining cream mixture and return liquid to saucepan. Discard any solids left in sieve.

6. In a slow stream, pour half of cream mixture over yolk-sugar mixture, whisking constantly until blended.

7. Return pan to stovetop over low heat. Whisking constantly, stream yolk-cream mixture back into pan.

8. With a wooden spoon, continue stirring until mixture registers 165 to 180 degrees on an instant-read thermometer, about 2 minutes. Do not heat above 180 degrees, or eggs in base will scramble. Mixture should be slightly thickened and coat back of spoon, with steam rising, but not boiling. (If you blow on the back of the spoon and the mixture ripples, you've got the right consistency.)

9. Pour into a clean airtight container and refrigerate for 12 to 24 hours.

10. Process in an ice cream maker according to manufacturer's instructions.

11. Meanwhile, preheat oven to 325 degrees.

12. Spread almonds in a single layer on a baking sheet. Toast in oven for 5 to 10 minutes, or until fragrant and golden. Remove from oven and let cool.

13. Transfer churned ice cream to a bowl and stir in toasted almonds.

14. Scrape into an airtight storage container. Freeze for a minimum of 2 hours before serving.

15. Top with a sprinkling of sea salt.

Suggested Cookies:

Pretzel Chocolate Chunk (page 202) or

S'mores (page 209)

Coolhaus Sandwich Creation:

David Rocky Roadwell: S'mores Cookies + Nutella Toasted Almond Ice Cream (see Building the Perfect Sandwich, page 25)

Recipe excerpted from COOLHAUS © 2014 by Natasha Case and Freya Estreller. Reproduced by permission of Houghton Mifflin Harcourt. All rights reserved.

Related: Ladurée's Sweet Ascent: How a Fad Food Is Spawning an International Empire