Cooking device in a fast-food restaurant

FRYER

This appliance often uses hot oil to quickly crisp up foods like fries or chicken, commonly found behind the counter.

This clue points to a common kitchen appliance used in fast-food restaurants to cook foods like fries or chicken. The answer is "FRYER," which is a straightforward definition—no wordplay or tricks here. It’s the deep-fat cooking device that heats oil to crisp up food quickly, a staple in places like burger joints or diners. Think of the sizzling sound behind the counter, and you’ve got it.