Drive-in burger chain Sonic (SONC) is one of the few restaurant operators that can ignore what McDonald's (MCD) - Get Reportdoes with its all-day breakfast menu.

Investors should get in on this action before Sonic reports fiscal second-quarter earnings after the close Tuesday.

At $31, the stock may seem pricey at 25 times earnings compared to a price to earnings multiple of 21 for the S&P 500 (SPX) . Shares are down over 3% for the year to date and nearly 15% for the past 52 weeks. 

For the quarter that ended in February, analysts, on average, expect earnings of 16 cents per share on revenue of $127.73 million, translating to growth of 23% and 1.2%, respectively. For the full year ending August, earnings are projected to climb 18% to $1.31 per share, while revenue of $623.78 million would mark a 3% increase from the year-ago quarter.

So now's an ideal time to buy one of the fastest-growing restaurant chains in the U.S.. With fiscal 2016 earnings projected to grow at six times the rate of revenue, Sonic's profit margins and same-store sales are also climbing at impressive rates.

In its first quarter, for instance, Sonic posted a 5.3% rise in same-store sales, maintaining its recent track record of mid- to high-single-digit comparable-sales growth. Not only are more customers driving in to order, they're spending more money during each visit, as evidenced by its 28% rise in first-quarter earnings per share.

It's for this reason, analysts, on average, project Sonic's earnings to grow at an annual rate of 17% in the next five years, which would be more than three times the projected growth rate of S&P 500 index. With Sonic's shares priced at just 23 times forward estimates, in line with shares of McDonald's, Sonic is by far the better value.

And if that wasn't enough, Sonic pays an 11-cent per-share quarterly dividend that yields 1.37% annually. Buy now.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.