Preheat the oven to 180°C (350°F). Roll the shortcrust pastry gently on a floured surface. Carefully place it into a quiche pan. Press it into the corners and trim extra edges. Prick the base with a fork.

Place baking paper over the pastry. Add baking beans or rice on top. Bake for about 10 minutes. Remove the paper and beans. Bake again for five minutes until slightly golden.

Heat a frying pan over medium heat. Add chopped bacon pieces. Cook until crispy and lightly browned. Stir occasionally so they cook evenly. Remove the bacon and place on paper towel to drain excess fat.

Using the same pan, melt a little butter. Add the chopped onion and cook slowly. Stir until soft and lightly golden. This step adds sweetness and depth to the quiche filling.

In a mixing bowl, whisk the eggs gently. Add heavy cream and milk. Continue whisking until smooth and creamy. Sprinkle in salt, pepper and nutmeg. This mixture forms the silky custard filling.

Spread cooked bacon and sautéed onions over the pastry base. Sprinkle grated cheese evenly on top. Slowly pour the egg and cream mixture over everything. Make sure the filling spreads evenly across the pan.

Place the quiche in the oven carefully. Bake for about 30 to 35 minutes. The center should look set but slightly soft. The top should turn lightly golden and smell amazing.

Remove the quiche from the oven and let it cool for ten minutes. This helps the filling firm up. Slice carefully and serve warm or at room temperature.