No crust means more time for you. Pair with a nice salad and a glass of South Island Sauvignon Blanc, Pomona Winds Pinot Grigio or Long Gamma White.
Preheat oven to 425F 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 over the top.
Whisk together eggs, cream, milk, and ½ teaspoon pepper and pour over cheese. Bake until top is golden and custard is set in the center, 20 to 25 minutes. Cool slightly before cutting into wedges.