Preheat and prep: Set your oven to 350°F (175°C). Line a 9x5-inch loaf pan with parchment paper, letting it hang over the long sides for easy lifting. Lightly grease the exposed ends.

Mix dry ingredients: In a large bowl, whisk 2 cups almond flour, 3 tablespoons coconut flour, 1 tablespoon baking powder, 1/2 teaspoon salt, and 1 teaspoon cinnamon. Break up any clumps so the batter mixes evenly.

Mash the bananas: In a separate bowl, mash bananas until mostly smooth. You want about 3/4 cup mashed. The riper the bananas, the stronger the flavor and natural sweetness.

Whisk wet ingredients: To the bananas, add 3 large eggs, 1/3 cup granulated sugar substitute, 1/3 cup Greek yogurt or sour cream, 1/4 cup melted butter or avocado oil, 2 tablespoons unsweetened almond milk, and 2 teaspoons vanilla. Whisk until smooth.

Combine: Pour the wet mixture into the dry mixture. Stir gently with a spatula until just combined. The batter will be thick but spreadable. If it seems dry, add 1 to 2 more tablespoons almond milk.

Fold in add-ins: If using, fold in 1/2 cup chopped walnuts or sugar-free chocolate chips. Keep add-ins moderate so the loaf bakes through evenly.

Fill the pan: Scrape the batter into the prepared loaf pan and smooth the top. For a bakery-style look, score a shallow line down the center with a spatula.

Bake: Bake for 45–60 minutes, until the top is golden and a toothpick inserted in the center comes out mostly clean with a few moist crumbs. If the top browns too quickly, tent with foil during the last 15 minutes.

Cool completely: Let the loaf cool in the pan for 15 minutes, then lift it out using the parchment and cool on a rack for at least 1 hour. Do not slice while hot—almond flour breads need time to set for a clean slice.

Slice and serve: Cut into 10–12 slices. Enjoy plain, warmed with a little butter, or topped with a spoonful of Greek yogurt and cinnamon.