Preheat oven to 350

Heat butter and oil in lg. skillet. Add onion and garlic and cook 2 min. Add zucchini and yellow squash. Cover and cook over medium heat 15 min. stirring occasionally. With a slotted spoon transfer mixture to a buttered 2 qt. casserole.

Combine eggs, half and half, salt, pepper, and thyme. Pour over squash and mix well. Bake 35 min. Remove from oven and top with panko and cheese. Place under broiler and broil until brown, about 3 min.