Preheat the oven to 400 degrees. Saute 2 tablespoons minced yellow onion and 1 garlic clove, minced, in a small skillet coated with nonstick cooking spray for 2 minutes; remove from heat. Add 5 ounces lean ground turkey, 2 teaspoons skim milk, 1/2 beaten egg, 3 tablespoons whole wheat bread crumbs, 1 teaspoon mustard, 1 teaspoon Worcestershire sauce, and 1 teaspoon capers; mix to combine. Place turkey mixture in a small muffin tin coated with nonstick cooking spray; bake 15 minutes. Serve with 1 1/2 cups steamed green beans tossed with 1 tablespoon lemon juice and a drizzle of olive oil.