Preheat oven to 375 degrees F. Lightly grease a 9x13-inch baking pan.
Make the Crumb: In a medium bowl, whisk together the flour, sugar, baking powder and salt. Use a fork or pastry cutter to blend in the butter, and then the egg (the dough will be crumbly). Press half of dough into the prepared pan and bake for 8 to 10 minutes, until light golden brown. Set on a wire rack to cool.
Make the Filling: In a separate large bowl, beat the cream cheese and sugar on medium speed with an electric mixer until smooth, about 2 to 3 minutes. Add the vanilla extract and mix to combine. Using an offset spatula, spread the cream cheese mixture into an even layer over the crust. Spoon the cherry pie filling in an even layer over the cream cheese mixture. Crumble the remaining dough evenly over the cherry layer.
Bake for 45 to 50 minutes, or until the top is light golden brown. Cool completely before adding the glaze.
Make the Powdered Sugar Glaze (if using): In a small bowl, whisk together the powdered sugar, cream and vanilla extract. Add more cream if you want a thinner glaze, or more powdered sugar if you want a thicker glaze. Drizzle over the bars and allow to set.
The bars can be served at room temperature or chilled. Leftovers can be stored in an airtight container in the refrigerator for up to 4 days.