Preheat oven to 350 degrees F (175 degrees C). Line 6 cups of a 12 cup muffin tin with paper baking cups or brush generously with oil, set aside.
In a medium bowl, sift coconut flour, baking soda and salt, whisk to combine. In another medium bowl, add unsweetened coconut milk, stevia, melted coconut oil, eggs, and vanilla, whisk thoroughly. Pour liquid ingredients into bowl with dry ingredients, stir to combine for one minute as coconut flour absorbs liquids. Fold diced strawberries into muffin batter.
Spoon muffin batter into the prepared tin, smoothing tops, then press a strawberry slice on the top of each. Bake muffins until golden brown, about 30 to 35 minutes. Cool, serve.