Preheat the oven to 350F.
Line 12 muffin cups with silicone muffin liners or parchment paper muffin liners.
In a large mixing bowl, combine the almond flour, sweetener, salt, baking powder, and pumpkin pie spice using a spatula.
In another mixing bowl, combine the pumpkin puree, eggs, butter and vanilla using a hand mixer.
Add the wet mixture to the dry and mix with a spatula until no dry ingredients remain.
Scoop the batter into prepared muffin cups filling around ¾ of each cup. Bake for 22-25 minutes on a lower rack, or until golden brown and a toothpick comes out dry after being inserted into the center of a muffin.
Remove from the oven and let the muffins cool down in the muffin pan until just warm to the touch. Then, place the muffins on the cooling rack and let them completely cool down before serving.