Step 1

Coat a grill or grill pan with cooking spray; preheat to medium-high.

Step 2

Pound chicken until about 1/4-inch thick; place on a large baking sheet.

Step 3

In a medium bowl, combine oil, vinegar, dill, oregano, salt, garlic powder and pepper; drizzle over chicken and flip to coat both sides. Let chicken sit for 10 minutes.

Step 4

Meanwhile, in a small bowl, combine cheese, milk and onion; mash together with a fork to make a spread.

Step 5

Grill chicken, flipping once, until browned and cooked through, about 2-3 minutes per side.

Step 6

Place chicken on toasted bun bottoms; spread each with 1 heaping Tbsp feta spread. Top each with 1 piece lettuce and 1 slice tomato; cover with bun tops.

Step 7

Serving size: 1 sandwich