Preheat your oven to 350°F and line a 12-cup muffin tin with paper liners.
In a large bowl, whisk together four eggs, half a cup of melted butter, half a cup of granulated erythritol, a teaspoon of vanilla extract, and three-fourths of a cup of pumpkin puree.
In a separate bowl, whisk together one and a half cups of almond flour, two teaspoons of baking powder, a pinch of salt, and two teaspoons of pumpkin pie spice.
Add the dry ingredients to the wet ingredients and stir until well combined.
Divide the batter evenly among the prepared muffin cups, filling them about three-fourths full.
Bake for 20 to 25 minutes or until a toothpick inserted in the center comes out clean.
Let the muffins cool slightly in the pan before transferring them to a wire rack to cool completely.
Enjoy your sugar-free pumpkin muffins with some butter, cream cheese, or whipped cream if desired.