Line an 8x8 or 9x9 baking dish with aluminum foil. Lightly spray it with cooking spray; set aside. Preheat the oven to 350°.
Cream together butter and sugar. Scrape the bowl and add eggs one at a time; add vanilla and salt.
In a separate bowl, whisk together baking powder and flour. Slowly add flour mixture to the butter mixture. Remove 1/2 c. of the dough and set aside.
Press remaining dough into prepared baking dish. Pour cherry pie filling over dough and spread to cover. Drop remaining 1/2 c. dough over the pie filling.
Bake 50-55 minutes. Remove from oven and cool completely.
Prepare glaze by whisking milk and powdered sugar with a fork. Drizzle glaze over cooled bars. Cut and serve.