1. Preheat oven to 350 degrees. Heat oil in a small (8-inch) ovenproof nonstick skillet over medium heat. Cook mushrooms, bell pepper, onion, and garlic until almost tender, about 5 minutes. Transfer mixture to a medium bowl, and let cool slightly. (Reserve skillet.)

2. To mixture in bowl, add eggs, half-and-half, cream cheese, cheddar cheese, bread, 1/2 teaspoon salt, and 1/4 teaspoon pepper; stir until combined. (There may be a few chunks of cream cheese remaining.)

3. Pour egg mixture into reserved skillet; bake until set, about 30 minutes. Heat broiler, and broil until top is golden brown, 2 to 3 minutes. Let stand 10 minutes before cutting into wedges and serving.