Preheat oven to 425 degrees. Coat a 9 x 9” baking pan with cooking spray.
In a microwave-safe bowl, add onions and butter. Cook in microwave on high for about 4 minutes until softened. Set aside.
In a large bowl, mix together cream-style corn, sausages, dried cranberries, egg, milk, sage, thyme, and black pepper. Blend well. Stir in cornbread mix and only stir until blended. The batter will be a bit bumpy. Spread cornbread batter into prepared pan. Spread evenly.
Spoon cooked onions/butter and liquid left in the bowl and using a rubber spatula spread evenly over the top.
Spoon the yogurt in small dollops evenly over the onions. Using the same rubber spatula, carefully spread yogurt a little but keep the dollops.
Sprinkle cheese evenly over top of yogurt.
Bake for 40-45 minutes so the entire casserole will be cooked through. It will look very golden brown.
Let stand for 10 minutes before cutting into 12 squares if served as a side dish and 6 slices for the main course. This casserole may be baked ahead of time, refrigerated and reheated. It also freezes great.