Set strawberries out to thaw (or run under cool water to thaw quickly).
Preheat oven to 375° F. Spray a muffin tin with cooking spray, or fill with paper liners.
In a small bowl, combine the flour, sugar, baking soda, and nutmeg.
Melt the butter in a small bowl, then whisk in the yogurt, eggs, and vanilla. Add to the dry ingredients and stir just until moistened.
Chop strawberries and fold them into batter.
Fill each muffin cup two-thirds full, and bake for 15-18 minutes or until a toothpick inserted near the center of a muffin comes out clean. Cool for 5 minutes in the pan, then remove from pan and transfer to a wire rack until cooled completely.
Garnish with powdered sugar before serving if desired.