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Chipotle Mexican Grill sign hangs above one of the Chain's restaurant in the trendy Bucktown neighborhood January 26, 2006 in Chicago, Ill. - 

Steve Chiotakis: As far as earnings reports go today, we'll also hear from investor darling Chipotle Grill. Chipotle's expected to wow the market with another strong quarter as Americans continue their lunch affair with the bulky burrito.

Marketplace's Jeff Horwich went looking for Chipotle's secret salsa.

Jeff Horwich: Wrap your hands around this: If you had bought $100 of stock in Chipotle a year ago, today you'd have $250. That's like enough for seven Three-Burrito Challenges on YouTube.

Seth Jayson: Chipotle has made me an awful lot of money.

Seth Jayson writes for the Motley Fool, where they're free to eat the rewards of the stocks they research. Chipotle is adding 140 stores this year, and packing more people into the ones it's got. Jayson credits an unchanging menu that actually changes more than we know.

Jayson: Just putting a different type of corn into one of the salsas, or treating the chili peppers a slightly different way to get more essential oil out. There are very few restaurant companies, I think, out there that would bother to do that.

Jayson says Chipotle has had the stomach to do one simple thing well.

Jayson: I think that's part of the charm of Chipotle. You don't have to say to yourself: "Geez, do I really need to try the McGriddle -- is there's going to be syrup in the bread of my sandwich?"

Things did get a little sticky last year when Chipotle fired hundreds of workers in Minnesota and D.C. after a federal immigration audit. Morningstar analyst R.J. Hottovy says the fallout hasn't hit the bottom line. A bigger challenge: food prices.

R.J. Hottovy: Beef and pork; avocados are at a multi-year high as well. Basically every commodity that they pay for stands above historical averages with the exception of chicken.

The company is about to test whether the Chipotle magic works beyond the burrito. Its new Asian chain, called ShopHouse, rolls out this summer.

I'm Jeff Horwich for Marketplace.

Follow Jeff Horwich at @jeffhorwich