Preheat the oven to 350 degrees and grease the muffin tins.
Whisk flour, baking powder, and salt in medium bowl until combined.
In another medium bowl whisk the egg until well-combined and light-colored, about 20 seconds. Then add sugar and whisk vigorously until well combined.
Slowly stream in the melted butter. Add greek yogurt in 2 additions, whisking just to combine.
Add frozen berries to dry ingredients and gently toss just to combine.
Add greek yogurt mixture to the dry mixture and fold with rubber spatula until batter comes together and berries are evenly distributed, careful not to over mix the batter.
Drop batter into greased muffin tin. (Or you can use muffin liners)
Bake until light golden brown and insert toothpick into the center of muffin comes out clean, 25 to 30 minutes.
Let sit in the pan for 5 minutes than move to a cooling rack.