While many growth stocks have suffered in 2021, one surprising name from the group hasn't skipped a beat: Chipotle (NYSE: CMG). Shares are up 36% year to date and 55% over the past twelve months. While it's tempting to automatically assume there's no upside left for a stock that has risen so much in such a short period of time, this surface-level conclusion is likely wrong. In this case, the stock's soaring price is evidence of the company's incredible execution. In fact, it's possible that the market has yet to fully appreciate Chipotle's business momentum. Here's exactly why Chipotle is a stock investors should consider buying today. Image source: Getty Images. Rapid growth The fast-casual burrito maker's recent momentum is impressive by just about every measure. Benefitting from an easy comparison in the year-ago quarter when the company was negatively impacted by COVID-19 lockdowns and revenue grew only 4.8% year over year, second-quarter 2021 revenue skyrocketed 39% to $1.9 billion. Of course, this strong performance wasn't solely due to an easy comparison. Much of it has to do with impressive execution from the company. Consider that Chipotle's digital sales during Q2 increased about 49% year over year -- and that was on top of 216% growth in digital sales in the year-ago quarter. Further, the company opened 56 new restaurants while only closing five during Q2. It turns out that Chipotle's ongoing investments in data-driven marketing campaigns, drive-thrus, its digital loyalty program, new menu items, and operational efficiency are paying off nicely. Image source: Chipotle Mexican Grill. An attractive valuation While Chipotle's price-to-earnings ratio of about 90 may seem expensive on the surface, strong revenue growth combined with operating leverage should lead to huge earnings-per-share growth over the next five years, easily justifying this premium valuation. Indeed, analysts' consensus forecast for Chipotle's earnings-per-share growth over the next five years is a whopping 58% annualized. If investors are uneasy about analysts' optimistic outlook, consider management's commentary in Chipotle's second-quarter earnings report. "Strong restaurant level economics combined with significant restaurant growth should allow us to optimize earnings power for many years to come," said Chipotle CEO Brian Niccol in the company's second-quarter earnings release. The company's operating leverage is certainly showing up nicely in its recent financials. Chipotle's restaurant-level operating margin hit a record high of 24.5% in Q2 2021. Based on Chipotle's business momentum and its strong earnings potential, shares arguably look like an attractive long-term investment at their current valuation. 10 stocks we like better than Chipotle Mexican GrillWhen our award-winning analyst team has a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* They just revealed what they believe are the ten best stocks for investors to buy right now... and Chipotle Mexican Grill wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of September 17, 2021 Daniel Sparks has no position in any of the stocks mentioned. His clients may own shares of the companies mentioned. The Motley Fool owns shares of and recommends Chipotle Mexican Grill. The Motley Fool has a disclosure policy.Source