Preheat the oven to 450 degrees F.
Generously butter a muffin tin. Whisk together the flour, salt, eggs, milk, and melted butter until frothy. Adding the milk a little at a time will help prevent lumps. The batter will be thin. Fill the muffin pans less than half full and bake at 450 for 20 minutes. Then reduce the temperature to 350 and bake 10 minutes more. DO NOT OPEN THE OVEN while the popovers are baking.
For the Strawberry Butter: 1/2 c. fresh strawberries, diced (ripe, sweet strawberries are the best)
1 c. (2 sticks) butter, softened
1/4 c. powdered sugar
In a large bowl cream butter with a hand mixer until whipped and smooth. Add powdered sugar and mix well. Fold in diced strawberries until butter is light pink and creamy. Store in the refrigerator.