My aunt always made this pie. I spent a lot of time looking for a recipe that made me think of hers. This was the moment!

 

Heat your oven to 350°F (175°C) before using it.
Make caramelized onions: In a big pan, melt the butter on medium heat. Put the cut onions in the pan and cook them, stirring from time to time, until they turn golden and caramelized, which should take around 20 minutes.
Make the pie crust: Spread the cooked onions evenly on the bottom of your already baked pie crust.
Mix the eggs, milk, and heavy cream in a bowl until well combined. Mix the shredded cheese, salt, and pepper.
Put the egg mixture on top of the onions in the pie crust and bake. Add paprika on top for a touch of color and a subtle smoky taste. Put the pie on a baking tray and bake for 40-45 minutes, until the middle is firm and the top is slightly golden.
Let it rest: Wait for the pie to sit for at least 10 minutes before cutting it. This helps it solidify and makes it simpler to serve.