The latest earnings results from Chipotle Mexican Grill (NYSE:CMG) confirm that the fast-casual restaurant company is the top growth story in the industry. Even in the face of rising food costs, Chipotle delivered one of its best quarters as a public company.

Shares of Chipotle surged more than 11% the day after the company's earnings announcement. However, shares are still attractive at current levels, as the company remains in a relatively early stage of growth.

Source: Company Facebook

Sizzling earnings
Burritos aren't the only hot thing at Chipotle: The company's growth has been hot for a while now. However, this quarter was a particular standout.

The company's same-store sales growth for the quarter was among the highest ever reported by Chipotle since going public in 2006. Comparable sales increased 17.3% in the second quarter, driven primarily by an increase in foot traffic as well as an increase in the average check size. The average check increase was due partially to the nationwide menu increase Chipotle completed by the end of the quarter.

The company also opened 45 new store locations in the quarter and 89 year to date. As a result, in the second quarter, revenue increased an impressive 28.6% on a year-over-year basis. Diluted earnings per share also increased 24.1% on a year-over-year basis.

Chipotle's reported revenue of $1.05 billion and diluted earnings per share of $3.50 both represented significant beats. On average, analysts expected the company to post revenue of $990 million and diluted EPS of $3.09.

All of this growth was achieved in an atmosphere that has proven to be challenging. The company's food costs have been rising and the restaurant level operating margin has been declining, mainly due to the steadily increasing price of beef, avocados, and dairy in addition to aggressive marketing.

Aggressive expansion
The most impressive aspect of Chipotle's growth story is perhaps that it shows no signs of stopping any time soon, even though the company already has a rather large domestic presence.

As of June 30, Chipotle had 1,681 restaurant locations. The company plans to grow its restaurant count by a range of 180-195 net locations this year, which represents 11.3% growth at the low end and 12.2% growth at the high end.

Compared to competitor Panera Bread (NASDAQ:PNRA.DL), which had 1,800 locations as of April 1, Chipotle's growth is impressive. In Panera's first quarter earnings release, company management stated that it planned to open 115-125 net new bakery locations. This range represents only 6.5% growth at the low end and 7% growth at the high end.

Also, compared to Chipotle, Panera has struggled mightily to increase comparable sales growth. In the first quarter, Panera reported a meager 0.1% increase in company-owned same-store locations.

The larger and more important part of the Chipotle growth story is twofold: international expansion and growth via new brands. At the end of last quarter, the company only had 10 restaurant locations in Europe. There is no reason that the company's strong brand will not translate well abroad, and so Europe will likely remain a viable growth opportunity for Chipotle going forward.

However, the company's two new restaurant themes, ShopHouse and Pizzeria Locale, are only just getting started. With former Chipotle management teams at each, the new brands will take some of the pressure off of the company's Mexican-themed restaurants while at the same time increasing its consumer base and creating new streams of revenue.

Chipotle CFO Jack Hartung explained on the most recent conference call:

We continue to believe that the best use of our cash is to invest in our high returning restaurants, and we'll continue to develop additional growth options by planting seeds including ShopHouse, Pizzeria Locale, and Chipotle outside of the U.S. And we expect each of these proceeds will provide attractive value-enhancing growth investments in the future.

(Source: Company Facebook)

Bottom line
Despite already massive success and a skyrocketing share price, Chipotle remains the best growth investment in the restaurant industry. Investors have a tremendously strong growth story in the company's Mexican-themed brand but also now have exposure to other cuisines as a result of Chipotle's new brands, which reduces overall risk considerably.