Preheat oven to 350°. In a large skillet, heat oil over medium-high heat. Add mushrooms and onion; cook and stir until tender, 4-6 minutes., Cut each biscuit into 8 pieces; place in a greased 13x9-in. baking dish. Top with mushroom mixture., Cook broccoli with cheese sauce according to package directions. Spoon over mushroom mixture., In a large bowl, whisk eggs, milk and seasonings; pour over top. Sprinkle with cheese. Bake until golden brown, 25-30 minutes.