Preparation Preheat oven to 425°F with rack in middle. Butter quiche dish, then sprinkle all over with bread crumbs. Cook onions with ham in butter in a 12-inch heavy skillet over medium-high heat, stirring occasionally, until pale golden, about 5 minutes. Spread in dish, then evenly sprinkle cheese on top. Whisk together eggs, cream, milk, and 1/2 teaspoon pepper and pour over cheese. Bake until top is golden and custard is set in center, 20 to 25 minutes. Cool slightly before cutting into wedges.
Preparation Preheat oven to 425°F with rack in middle. Butter quiche dish, then sprinkle all over with bread crumbs. Cook onions with ham in butter in a 12-inch heavy skillet over medium-high heat, stirring occasionally, until pale golden, about 5 minutes. Spread in dish, then evenly sprinkle cheese on top. Whisk together eggs, cream, milk, and 1/2 teaspoon pepper and pour over cheese. Bake until top is golden and custard is set in center, 20 to 25 minutes. Cool slightly before cutting into wedges.