Preheat the oven to 375°F. Grease or line a standard cupcake pan with 8 muffin cups. Place the butter in a medium-sized microwave safe bowl. Microwave on high, uncovered, for 30 seconds or until melted. Add the sweetener, almond flour, coconut flour, salt, garlic powder, baking powder, xanthan gum, eggs, fresh thyme, almond milk and cheddar and mix well with a fork. Spoon the batter into the muffin cups, about 2/3 full. Bake for 22 minutes, or until a toothpick inserted in the center comes out clean.