Remove the frozen pie crust from the freezer and let it thaw for 10 minutes at room temperature to make it easier to work with. While it thaws, preheat your oven to 350°F. Once thawed, place the crust in a 9-inch pie dish (or the size specified on your package) and prick the bottom with a fork a few times to prevent it from puffing up during baking. Pre-bake the crust for 8-10 minutes until it's just set but still pale—this prevents a soggy bottom in the finished quiche.

Melt the butter in a large skillet over medium-low heat. Add the sliced onions and 1/4 teaspoon of salt, then reduce the heat to low. This is where patience pays off—cook the onions for 30 minutes, stirring occasionally (every 5-7 minutes), until they're deeply golden, soft, and sweet. The low heat allows the natural sugars in the onions to develop slowly without browning too quickly. I like to let the onions cook undisturbed between stirs so they can make contact with the hot pan and build flavor. The longer, gentler cooking creates that luxurious caramelized depth that makes this quiche special.

While the onions are caramelizing, crack the eggs into a medium bowl and whisk them together with the heavy cream, milk, 1/4 teaspoon of black pepper, and 1/4 teaspoon of salt. Whisk until the mixture is uniform and slightly frothy—about 1-2 minutes. Room temperature eggs blend more smoothly and create a creamier custard than cold ones. Set this mixture aside until you're ready to assemble the quiche.

Remove the pre-baked pie crust from the oven and let it cool for just a minute. Spread the caramelized onions from Step 2 evenly across the bottom of the crust, then scatter the crumbled goat cheese over the onions. Pour the custard mixture from Step 3 slowly over the filling, allowing it to settle around the onions and cheese. I like to gently arrange some of the caramelized onions on top of the custard for a nice presentation—this also helps prevent the filling from puffing up too much. Place the quiche in the 350°F oven and bake for 40-45 minutes, until the center is just set but still slightly jiggly when you gently shake the pan (it will continue to set as it cools).

Remove the quiche from the oven and let it rest at room temperature for 10 minutes. This resting period allows the custard to set completely and makes slicing cleaner. Serve warm or at room temperature—both are delicious. If you'd like to serve it later, the quiche reheats beautifully at 325°F for 10-15 minutes.