Preheat oven to 400°F (200°C).

Heat a large skillet over medium-high heat and lightly coat with cooking spray. Add the ground beef, breaking it apart with a spatula. Cook for 6-8 minutes until completely browned with no pink remaining. Drain any excess fat thoroughly.

Add the diced onion to the beef and cook for 3-4 minutes until softened and translucent. Remove from heat and stir in the chopped dill pickles.

In a small bowl, whisk together the Greek yogurt, ketchup, pickle relish, white wine vinegar, garlic powder, onion powder, and salt until completely smooth. Taste and adjust seasonings if needed.

Spread the beef mixture evenly in an 8x8 inch baking dish. Sprinkle the shredded cheddar cheese over the top, then drizzle the special sauce across the cheese layer.

Bake for 15-20 minutes until the cheese is melted, bubbly, and has golden brown spots around the edges. Let cool for 5 minutes before serving.