Investors interested in Retail - Restaurants stocks are likely familiar with Bojangles (BOJA) and Starbucks (SBUX). But which of these two companies is the best option for those looking for undervalued stocks? Let's take a closer look.We have found that the best way to discover great value opportunities is to pair a strong Zacks Rank with a great grade in the Value category of our Style Scores system. The proven Zacks Rank puts an emphasis on earnings estimates and estimate revisions, while our Style Scores work to identify stocks with specific traits.Right now, Bojangles is sporting a Zacks Rank of #2 (Buy), while Starbucks has a Zacks Rank of #3 (Hold). Investors should feel comfortable knowing that BOJA likely has seen a stronger improvement to its earnings outlook than SBUX has recently. However, value investors will care about much more than just this.Value investors are also interested in a number of tried-and-true valuation metrics that help show when a company is undervalued at its current share price levels.Our Value category highlights undervalued companies by looking at a variety of key metrics, including the popular P/E ratio, as well as the P/S ratio, earnings yield, cash flow per share, and a variety of other fundamentals that have been used by value investors for years.BOJA currently has a forward P/E ratio of 20.52, while SBUX has a forward P/E of 24.12. We also note that BOJA has a PEG ratio of 1.64. This metric is used similarly to the famous P/E ratio, but the PEG ratio also takes into account the stock's expected earnings growth rate. SBUX currently has a PEG ratio of 1.79.Another notable valuation metric for BOJA is its P/B ratio of 2.03. The P/B is a method of comparing a stock's market value to its book value, which is defined as total assets minus total liabilities. By comparison, SBUX has a P/B of 73.12.Based on these metrics and many more, BOJA holds a Value grade of B, while SBUX has a Value grade of C.BOJA has seen stronger estimate revision activity and sports more attractive valuation metrics than SBUX, so it seems like value investors will conclude that BOJA is the superior option right now.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report To read this article on Zacks.com click here. Zacks Investment Research