Tex-Mex Keto Squash Casserole

Name: Tex-Mex Keto Squash Casserole
Prep time: 15 min
Cook time: 20 min
Total time: 35 min
Cuisine: American
Ingredients: 1 tsp olive oil; 2 pounds summer squash, sliced; 1 cup diced onion; 1 can ro*tel tomatoes, drained (may use mild if desired); 1 ½ cups cheddar cheese,grated (reserve 1/2 cup for topping); ½ cup sour cream; ½ cup mayonnaise; ¼ tsp salt; ¼ tsp black pepper