Preheat Oven to 375°F
Heat 1 tbsp of butter in a pan over medium-high heat.
Sauté leeks until caramelized, about 10-15 minutes.
Once caramelized, add the cider or unsweetened apple juice and scrape the bottom of the pan. Continue to cook until most of the juice has evaporated.
Remove from heat and add diced apples. Set aside.
In a large mixing bowl, combine almond flour, salt and pepper. Whisk until combined.
Add the eggs to the flour mixture and whisk until thoroughly combined.
Slowly pour in tbe whipping cream and almond milk and continue to mix until combined.
Pour the filling into a 9-inch deep pie dish (with pre cooked pie shell) and sprinkle the diced brie cheese, leeks, and apples on top of the mixture. NOTE: If using a regular size pie dish, you will have leftover filling.
Cover the edges of the pie crust with aluminum foil (almond flour tends to burn easily) and bake in the oven for approx 60 minutes. Depending on your oven and pie dish you may need more or less time. Start checking the quiche at around 45 minutes.
Once the center is barely set, remove the quiche from the oven and let sit for 10-15 minutes.
Serve on its own or with a simple side salad and enjoy!