Preheat your oven to 350°F. Lightly coat a 9x13-inch baking pan with non-stick spray and set it aside.

For the crumb topping, in a medium bowl, mix flour, sugar, and cinnamon. Add melted butter and stir with a fork until crumbly. Set aside.

In another medium bowl, whisk together flour, pumpkin pie spice, baking soda, baking powder, and salt. Set aside.

In a large bowl or using a stand mixer, cream butter and sugar until light and fluffy, about 2 minutes. Beat in eggs until smooth, then mix in vanilla, pumpkin, and sour cream. Gradually add the flour mixture, alternating with milk, until the batter is well combined.

Pour the batter into the prepared baking pan. Sprinkle the crumb topping evenly over the batter and gently press it down with your hands. Bake for 50 to 55 minutes, or until a toothpick inserted into the center comes out clean. If the top starts to brown too quickly, cover lightly with foil.

Let the cake cool for 15 minutes or completely, as preferred.

For the glaze, in a small bowl, whisk together all glaze ingredients until smooth. Drizzle over the cake, whether warm or cooled. Slice and serve.