Shares of Chipotle Mexican Grill (CMG 6.24%) have been punished in recent weeks as the major indexes tumbled. Meanwhile, there has been little doubt in my mind that the sell-off in the restaurant company was a prime buying opportunity. After reading the latest earnings results from Chipotle today, it seems my hunch was correct: The company continues to excel in all areas.

Source: Chipotle.

Earnings results
On a year-over-year basis, Chipotle grew first-quarter revenue by 24.4% to $904.2 million; results were driven by a healthy 13.4% increase in comparable-restaurant sales. This increase in same-store sales was a result of both higher traffic and an increase in average check and represents the company's highest increase in comp sales in the last five quarters.

Chipotle founder and co-CEO Steve Ells explained in the company's report:

We are delighted that more and more people are choosing to visit our restaurants every day allowing us to deliver double digit comps during the quarter. Our food culture has always been a defining characteristic of Chipotle and continues to set us apart from other restaurants.

Net income increased 8.5% to $83.1 million, and diluted earnings per share rose 7.8% to $2.64. The company's earnings were affected by increases in commodity costs driven by pressure in beef, cheese, and avocado prices. In the quarter, food costs represented 34.5% of total revenue, which was up 150 basis points. Also, the restaurant operating margin decreased 40 basis points, which was primarily due to higher food costs as well.

Going forward
In addition to solid first-quarter results, Chipotle management also offered impressive guidance. The company expects high-single-digit comparable sales growth for this year, which does not include any potential menu increases.

Regarding same-store sales growth, Ells stated: "We are confident that our special food culture will continue to attract more customers to visit Chipotle as customers better understand and connect how natural and high quality ingredients that are freshly prepared result in better tasting food."

Also, management expects to open 190 to 195 new restaurants in 2014, 44 of which were already opened in the first quarter. At the end of the most recent quarter, the company's total restaurant count stood at 1,637.

Changing focus
One of the more encouraging signs at Chipotle is the company's increasing focus on new restaurant brands. While ShopHouse, the company's fast-casual take on Southeast Asian food, and Pizzeria Locale, its take on custom pizza, are still a small part of the overall store count, management has been growing each concept's presence methodically.

The ongoing success of the Chipotle Mexican Grill brand, which shows no signs of stopping anytime soon, means even better things for ShopHouse and Pizzeria Locale in the future. Since management continues to display an ability to increase same-store sales at robust levels, growth of the two new restaurant brands has massive long-term potential for the company and its investors.

Not only will the new brands help to maintain the company's growth trajectory, they will also decrease a dependence on the signature Mexican-themed brand.

In fact, Chipotle is beginning to look a lot like Yum! Brands (YUM -0.31%). If the company can create lasting brands in ShopHouse and Pizzeria Locale, Chipotle will have three main restaurant chains, two of which are very similar in theme to Yum!'s Taco Bell and Pizza Hut chains.

While Chipotle appears to be a Yum! Brands in the making, it is also a more efficient company with a more affluent consumer base. Although Chipotle's restaurant margin decreased slightly in the most recent quarter to 25.9%, it still remains far above Yum! Brands' restaurant margin of 15% as reported in the fourth quarter.

The company also has superior profit and operating margins of 10.2% and 16.8%, respectively, versus Yum!'s respective margins of 8.3% and 15.5%.

Source: Yum! Brands.

Bottom line
Not only is Chipotle continuing to grow its main Mexican-themed chain in a way that belies the brand's already large presence, management is now focusing on two new restaurant brands as well. This will likely create a perfect storm for investors going forward. The company's overall growth should remain at high levels, while risk should lessen significantly thanks to the company's increasing portfolio diversity.