Prep the pan: Heat the oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners or lightly grease.
Mix dry ingredients: In a large bowl, whisk almond flour, coconut flour, baking powder, salt, and sweetener until no lumps remain.
Combine wet ingredients: In a separate bowl or large measuring cup, whisk eggs, melted butter, sour cream, almond milk, and vanilla until smooth.
Make the batter: Pour wet ingredients into dry.
Stir with a spatula until just combined. The batter will be thick but scoopable. If it’s too dense, add 1–2 teaspoons more almond milk.
Fold in chips: Gently fold in the white chocolate chips, reserving a tablespoon to sprinkle on top.
Portion: Divide the batter evenly among the muffin cups, filling each about 3/4 full.
Top with remaining chips.
Bake: Bake 18–22 minutes, until the tops are set and lightly golden and a toothpick comes out with a few moist crumbs.
Cool: Let muffins cool in the pan for 10 minutes, then transfer to a rack to cool completely. This helps them set and prevents crumbling.
Enjoy: Serve warm or at room temperature. The flavor deepens after a few hours as the sweetener settles.