Prep your pan and oven: Heat the oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners or lightly grease with baking spray.
Mix the dry ingredients: In a large bowl, whisk together 2 cups fine almond flour, 2 tablespoons coconut flour, 2 teaspoons baking powder, 1/4 teaspoon salt, and 1/2 to 3/4 cup granular sweetener (adjust to taste).
Whisk the wet ingredients: In a separate bowl, whisk 3 large eggs, 1/3 cup melted unsalted butter, 1/3 cup sour cream, and 1 1/2 teaspoons vanilla extract.
Add 1 teaspoon lemon zest if using.
Combine: Pour the wet mixture into the dry. Stir until just combined. The batter should be thick but scoopable.
If it seems too dry, add 1–2 tablespoons unsweetened almond milk.
Fold in strawberries: Gently fold in 3/4 to 1 cup diced strawberries (pat them dry first). Don’t overmix—just enough to distribute.
Fill the tins: Divide the batter evenly among the muffin cups, filling each about 3/4 full. For a bakery look, add a few extra strawberry bits on top.
Bake: Bake 18–22 minutes, or until the tops are set, 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.
They firm up as they cool, so resist cutting in too early.