Baked Apples With Pretzel Crumble Topping

3 halved, cored apples {I use red apples}
3 Tbsp cold unsalted butter
3 Tbsp all-purpose flour
4 1/2 teaspoons brown sugar
3 Tbsp crushed pretzels

Blend the butter, flour and brown sugar.
Stir in crushed pretzels.
Scatter over halved, cored apples.
Bake at 375 until apples are soft and topping is crisp {about 35-40 minutes}