Preheat oven to 375 degrees F. Line a muffin pan with paper liners.
Combine the butter, milk, and egg in a small bowl and beat it lightly. In a larger bowl, pour in your flour, salt, baking powder, and sugar and gently mix it. Toss in the chopped strawberries and sliced banana, then stir to coat with the flour mixture. Pour in your milk mixture and stir it all up together.
Fill up the muffin cups with your batter, then place in the oven and bake for 25 to 30 minutes.
Let them cool down for 10 minutes, then remove from the pan and serve these bad boys up.