Keto Chicken Potpie

Preheat oven to 425°. Make filling: In a large ovenproof skillet over medium-high heat, melt butter. Add onion, garlic, carrot, and celery and cook, stirring, until softened, about 7 minutes.  Stir in broth, thyme, and paprika and bring to a boil. Let simmer, 5 minutes, until vegetables are tender. Stir in heavy cream and simmer until thickened, about 2 minutes. Add chicken and peas and toss to warm through and coat with the sauce, about 2 minutes. Season with salt and pepper. Remove from heat.  Make crust: In a large microwave-safe bowl, melt together mozzarella and cream cheese. Add eggs and stir to combine, then stir in almond flour, and baking powder. Season with salt.  Dollop crust mixture over the filling and smooth the top with a spatula. Using a knife, cut an X in the center of the crust, then brush with egg wash. Bake until crust is golden, about 25 minutes.