Preheat your oven to 350°F. Grease a 9-inch round or square baking pan and set aside.
In a medium bowl, whisk together the flour, salt, cinnamon, pumpkin spice, baking soda, and baking powder.
In a large mixing bowl, cream the softened butter with the granulated sugar and brown sugar until light and fluffy. Beat in the egg and vanilla extract until well incorporated.
Add the pumpkin puree and Greek yogurt to the wet mixture, mixing until fully incorporated.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Be careful not to overmix.
Spread the cake batter evenly into the prepared baking pan.
In a medium bowl, combine the flour, brown sugar, and cinnamon. Add the cold, cubed butter and use a pastry cutter or your fingers to work the butter into the dry ingredients until the mixture resembles coarse crumbs. Set aside.
Bake in the preheated oven for 35-40 minutes, or until a toothpick inserted into the center of the cake comes out clean or with a few moist crumbs.
While that is baking, make your glaze. Once the cake has cooled for 10 minutes drizzle the vanilla glaze over the cake.
