Four years ago, Blue Apron was born from a tiny seed of an idea. Today, the New York-based meal-kit company is valued at more than $2 billion (it's also considering an IPO in the not-too-distant future, according to a Bloomberg report). But among the greatest challenges the company still faces, explains head of product Melody Koh, is continuing to scale.

Currently, Blue Apron is working to develop software that can manage the complexity involved with buying a variety of food products--notably, "specialty" crops such as Fairy Tale eggplants. Each week, the company delivers recipes and the ingredients required to cook those meals to customers, starting at $8.74 per person.

"Buying and procurement from the Blue Apron lens is very complicated," Koh said, speaking at a breakfast panel at the company's Chelsea headquarters on Friday. Often, "we actually have to work with farmers to say, 'please grow this for us.'"

Blue Apron's key to achieving scale is hiring engineers who can reduce the complexity of the supply chain. The main challenge is actually finding those employees. That's a point that Koh, along with the product leads at Squarespace and Stripe, all agree on.

"That's the $4 million dollar question," said Natalie Gibralter, who heads up product at Squarespace. The web-hosting company has likely seen some success on the hiring front, however, given that it currently boasts a more than $1 billion valuation, and sees revenue in excess of $100 million annually.

"Every day the business is growing, and you need to find people who are comfortable with that and who will roll with that," added Raylene Yung, Stripe's head of product engineering. The San Francisco payments processor handles billions of dollars worth of transactions, and was most recently valued at $5 billion in a July 2015 funding round.

Here are three key tips from the expert panelists on how to hire employees who can help the business scale:

1. Experience is key.

The best way to hire for scale is to choose employees who've previously worked at fast-growing companies. Those candidates tend to be more independent than others.

"Experience with scale is something you can't replicate," Yung says. "You [the worker] have seen systems grow, and you are just able to use your intuition. That is something that we look for."

2. Lazy developers are your most important assets.

It might sound contradictory, but as Yung puts it: "The best engineers are the laziest ones." They tend to be more efficient, she says, because they're used to creating shortcuts to accomplish more work in less time.

As Stripe continues to build more tools for software developers, Yung says she looks for employees who have their own productivity hacks. Gibralter agreed, noting that Squarespace has faced challenges with implementing new languages as the company expands internationally.

"We're looking for people who think about systems," she said. "How to get from one to two languages is really challenging, but you can build it out in such a way that you can then add one hundred languages [easily.]"

3. Seek those who are comfortable with uncertainty.

Ultimately, growing a startup in any industry is uncharted territory. That means that it's important to find those who are content with not knowing the right answer.

"We like to say that the biggest product we've ever worked on at Stripe is the product we're working on tomorrow," Yung explained. To that end, it's important to hire those who are comfortable -- and even inspired -- by not knowing what exactly lies ahead.

To achieve scale, find those who are "comfortable with not knowing," she said.