Neil Robertson has a few secrets. Kelly O

Before Crumble & Flake opens at 9 a.m. on Sunday morning, the line of customers stretches down the block. It moves quickly enough—the crowd files into the tiny Capitol Hill pastry shop four or five people at a time, they choose some pastries (it seems no one ever buys just one), and then they shuffle back out onto the sidewalk with their cups of coffee and paper bags filled with treats. Those still waiting outside crane their necks to peer through the window to see what's left.

Inside, the pastry case holds a small menu of magic—things like kouign-amann, chocolate croissants, paprika-and-cheddar croissants, fig-and-olive-tapenade rolls, salted-peanut-butter cookies, and cream puffs filled to order with vanilla, chocolate, or apricot filling.

Well, sometimes that's what's in the pastry case.

Wednesday through Friday, Crumble & Flake opens at 7 a.m. and they're nearly bought out by 10 a.m. On weekends, they open at 9 a.m. and their stock barely lasts an hour. If you're not there early enough, you run the risk of seeing little more than nearly empty shelves—or, worse, a closed sign and crumbs.

Crumble & Flake founder and pastry chef Neil Robertson (formerly of Canlis, Mistral Kitchen, and the Bellagio in Las Vegas) had no idea his new bakery would be so successful so fast.

"I was shocked," he says. "I mean, I liked what I was doing, but it's just a pastry! [On the first day] I was literally thinking, 'What am I going to do with all the leftover stuff at the end of the day?' Oh my God, it was not a problem.

"At the same time, it's great to be so popular," he says. "And we could use a satellite kitchen or reduce our offerings to make more room, but I want to stick with my vision—small batches made really carefully. I touch each piece myself to make sure it's right. That's what I want. And that's what I want to give people."

To make these small, perfect batches, Robertson starts working at 4:30 in the morning. He's been refining some of his recipes for years. And, despite the crowds, he claims a few of them are still not quite perfect enough. (He also admits he's a control freak—"Let's put it bluntly"—so take his claim of imperfection with a grain of salt.)

The croissants are almost always the first to go. They've been sold out two of the three times I've been to Crumble & Flake. An unthinkably crispy, deep golden outer layer hugs the tender, cloudlike insides. Tiny pockets of butter burst on your tongue when you sink your teeth into it.

"I'm really happy with the flavor [of the croissant]," Robertson says, preparing to whip some fresh whipping cream into a batch of vanilla custard for the cream puffs. "The texture's pretty good—it could be a little closer to what I have in mind. I have a really strong vision of what I want."

For the record, it is impossible to imagine the croissant getting any better.

Robertson is, rightfully, really happy with his chocolate chip cookie. It has crisp edges, a chewy center, and more chocolate chips than the average cookie, but not too many—there are still sections of chocolateless vanilla-tinged dough, as there should be. The texture is beyond any chocolate chip cookie I've ever had.

"This is radically different than other cookie recipes," he says. "It's what I wanted from a cookie. I want it to be really chewy—chewy! Not cakey, not underbaked, not raw," he says.

Achieving such a perfect balance of crispy and chewy is difficult for even the experienced baker. I ask if he's willing to share any tricks. He grins. "I've got a few secrets," he says. "I'm not ready to divulge any of them right now." (Cue endless calls from literary agents and publishers hoping to snag him for his first cookbook.)

Robertson's favorite item on the menu is the kouign-amann, which in Breton literally means "cake butter."

"It's a pure hit of butter," he says. "It's salty and sweet in equal measures. It doesn't really have much more butter than a croissant does, but it just tastes like butter personified." Read that last phrase again. Butter personified.

You also must try a Chewy-O, which is a sandwich cookie comprising two very dark, very chewy chocolate cookies and a sugary filling that is 100 times better than anything Nabisco could ever produce. It's not the kind of cream filling you want to put on everything; it's not the kind of cream filling you want to eat by the spoonful. It's specially created to complement the not-too-sweet but verging-on-too-chocolaty cookies, which are moist enough to squish up into a ball. (Try to do that with any other cookie, and you will make a mess and ruin your snack.)

The pastries are what bring the people to Crumble & Flake, but Robertson always wants people to know about the coffee from True North Coffee Roasters. It looks like drip, but it's not. It was given nearly as much thought as Robertson has given his macarons (which are, of course, wonderful—try the grapefruit ones).

"It's not just drip coffee. It has a fruitiness and rich chocolaty flavor that goes really well with the pastries," he says. "The coffeemaker is custom-made so there's this break in between the filter and the water. You put the coffee in, then it shoots a little bit of water to wet the grounds, then you stir it, then a bit more water, stir it again—there's agitation throughout the process. It gets a lot more extraction, and the finished product tastes a lot more like an Americano. It goes really nicely with the pastries. I really want people to know about the coffee. It's so good."

Robertson also wants people to know that he's sorry you have to start lining up an hour before they open in order to get your hands on some of his creations, but to maintain the high quality, that's just how it has to be.

"It's not what I intended. Unfortunately, it's probably gonna be the reality," he says. "I'm sorry for that. It's just gonna be the way it is. This is the business I wanted." recommended