Instructions:
- Preheat oven to 375°F (190°C). Lightly grease a 9-inch pie dish.
- Sauté the diced bacon in a large non-stick skillet until crisp. Remove bacon with a slotted spoon and set aside, leaving about 1 tablespoon of rendered fat in the pan.
- Sauté the chopped onion in the remaining fat until softened and translucent (about 5 minutes). Remove from heat.
- Scatter the cooked bacon, softened onions, and about 3/4 cup of the grated cheese evenly over the bottom of the prepared pie dish.
- In a large mixing bowl, vigorously whisk the 6 eggs until they are light and slightly frothy.
- Whisk in the whole milk, heavy cream, nutmeg, salt, and pepper until fully incorporated.
- Slowly pour the liquid custard mixture over the ingredients in the pie dish, ensuring even distribution. Top with the remaining reserved cheese.
- Bake for 35–40 minutes. The quiche is done when the edges are set and slightly puffed, and a knife inserted near the centre comes out mostly clean.
- Let the quiche rest on a wire rack for 10 minutes before slicing. Garnish with fresh chives, if using, and serve warm or at room temperature.