Preheat the oven to 375 F and prepare an eight-inch round pie pan.
In a double boiler, melt Gouda cheese on medium heat. Once fully melted, add in one egg, almond flour, salt, pepper, and mayo. Continue to cook until the mixture is homogeneous, using a spatula to stir it constantly.
Divide the dough into half then roll one of them between two pieces of parchment to a size that is slightly bigger than your baking pan. Place into the bottom of the pan and cover the edges using your hands. Trim the extra off the edges if necessary.
Roll the second part of the dough into the same size as the pan to cover the top of your pie for later. Place the dough in the refrigerator while you make the filling.
Heat oil in the frying pan. Add minced garlic, chicken, and sliced mushroom. When the chicken is cooked, add in the cream cheese. Season with salt and pepper.
Transfer the filling over the crust and cover the filling with the second part of the dough. Make sure the edges are tight. Use a fork to poke a few holes so it bakes evenly.
Bake in the oven for 25 minutes. Once golden, remove from heat. Serve with some mayo or tomato sauce and with some rosemary on top.