Preheat the oven to 350 degrees F. Line a muffin tin with paper cupcake liners.
In a large mixing bowl, cream together the butter and sweetener until light and fluffy.
Add the eggs, vanilla, cinnamon, and ginger, and mix again until well combined.
Add the almond flour, salt, baking soda, and baking powder, and stir until combined. Fold in the carrots and walnuts.
Spoon the batter into the lined cupcake tin. Fill each one almost completely full.
Bake at 350 degrees F for 20-25 minutes, or until cooked through and a toothpick pulls out clean from the center of a muffin. Let cool and enjoy.
If topping with optional frosting: Combine all frosting ingredients in the bowl of a stand mixer, then use the whisk attachment on high speed until the mixture is light and fluffy. If mixture is too thick, thin with another splash of heavy cream. Add a thin layer of frosting to each muffin and enjoy.