Prep your pan and oven. Heat oven to 350°F (175°C). Line a 12-cup muffin pan with paper liners or use silicone cups.
Mix dry ingredients. In a large bowl, whisk almond flour, coconut flour, sweetener, baking powder, baking soda, and salt until well combined.
Breaking up clumps now leads to a smoother batter.
Whisk wet ingredients. In a separate bowl, whisk eggs, almond milk, melted butter, vanilla, and lemon zest until smooth.
Combine. Pour wet ingredients into dry. Stir gently with a spatula until just mixed. The batter will be thick but scoopable.
Prep strawberries. Toss the diced strawberries with 1 tablespoon almond flour.
This helps prevent them from sinking and reduces excess moisture.
Fold in strawberries. Gently fold into the batter, saving a few pieces for topping if you like a pretty finish.
Fill the cups. Divide batter evenly among the 12 liners, filling each about 3/4 full. Top with reserved strawberry bits.
Bake. Bake 18–22 minutes, or until the tops are set and lightly golden and a toothpick comes out mostly clean (a few moist crumbs are fine).
Cool. Let muffins cool in the pan for 10 minutes, then transfer to a rack. They firm up as they cool, so be patient before peeling off liners.