Heat your oven to 375°F (190°C).
Spray a 12-cup muffin tin with nonstick cooking spray.
In a medium bowl, whisk together gluten-free flour, sugar, baking powder, baking soda, and salt.
In a large bowl, whisk together melted butter, milk, eggs, and vanilla extract.
Pour the dry ingredients into the wet ingredients and mix until just combined.
Gently fold in chopped strawberries. If you want, add some lemon juice, strawberry jam or preserves, walnuts, chocolate chips, or pecans.
Evenly distribute the batter among the muffin cups.
Bake for 20-25 minutes, until the muffins are golden brown and a toothpick inserted into the center comes out clean.
Let the muffins cool in the tin for 5 minutes.
Transfer them to a wire rack to cool completely.