Preheat and prep: Heat your oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners or grease well. Set aside.

Mix dry ingredients: In a large bowl, whisk 2 cups almond flour, 2 tablespoons coconut flour, 2 teaspoons baking powder, 1/2 teaspoon kosher salt, 2 teaspoons ground cinnamon, 1 teaspoon apple pie spice, and 1/2 to 2/3 cup granulated keto sweetener. Break up any clumps in the almond flour for a smooth batter.

Prep the apple: Core and finely dice about 1/2 cup apple (tiny cubes). Toss with 1 teaspoon lemon juice if you have it to prevent browning. Pat dry with a paper towel to remove extra moisture.

Combine wet ingredients: In a separate bowl, whisk 3 large eggs, 1/3 cup melted butter (cooled slightly), 1/2 cup unsweetened almond milk, and 1 teaspoon vanilla extract until smooth.

Make the batter: Pour the wet mixture into the dry ingredients. Stir until just combined. Fold in the diced apple. The batter will be thick, which is normal for almond flour muffins.

Fill the cups: Divide the batter evenly among the 12 muffin cups, filling each about 3/4 full. Use a scoop for tidy portions.

Optional cinnamon “streusel”: Mix 1 tablespoon granulated keto sweetener with 1/2 teaspoon cinnamon and a pinch of salt. Sprinkle evenly over the tops for a bakery-style finish.

Bake: Place in the center of the oven and bake 18–22 minutes. They’re done when the tops are set, lightly golden, and a toothpick comes out mostly clean with a few moist crumbs.

Cool: Let the 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. They pair nicely with coffee, tea, or a pat of butter.