Gluten-free banana Crumb Cookies

Name: Gluten-free banana Crumb Cookies
Prep time: 30 min
Cook time: 20 min
Total time: 50 min
Cuisine: American
Ingredients: COOKIES; 1 cup ripe banana (mashed); ½ cup unsalted butter (softened); ¾ cup brown sugar; ¼ cup white sugar; 1 large egg; 1 tsp vanilla extract; 2 cups gluten-free flour - I use Bobs Red Mill 1:1 but you can use any gluten-free flour. I haven't tried this with almond flour or coconut flour so I don't know how they would turn out; ½ tsp salt; ½ tsp baking powder; 2 tsp cornstarch; 1/2 cup butter; 2/3 cup gluten-free flour; 1/4 cup brown sugar; 1/4 cup granulated sugar; 1/2 teaspoon cinnamon; GLAZE; 1 cup powdered sugar; 1-2 tsp milk