Preheat your oven to 350℉. Line a 9” x 13” metal pan with parchment paper or spray it with baking spray. Set aside.
In a medium bowl, combine brown sugar and flour with a fork. Drizzle in the melted butter and combine. Set aside.
½ cup light brown sugar, ½ cup all-purpose flour, ¼ cup unsalted butter
In a large mixing bowl, combine pumpkin, eggs, water, vanilla, cinnamon, ginger, nutmeg, cloves, and cardamom with an electric mixer. Add in the cake mix and baking powder, and mix until just combined.
1 15- ounce can pumpkin puree, 2 large eggs, ½ cup water, 1 Tablespoon vanilla extract, 1 teaspoon ground cinnamon, ½ teaspoon ground ginger, ¼ teaspoon ground nutmeg, ¼ teaspoon ground cloves, ¼ teaspoon ground cardamom, 1 13.25- ounce yellow cake mix, ½ teaspoon baking powder
Pour the cake batter into the prepared pan and spread evenly. Top with the brown sugar crumble. Bake for 25-30 minutes or until a toothpick inserted in the middle comes out clean. Cool completely.
In a medium mixing bowl, whisk powdered sugar, vanilla, cinnamon, and 1-2 Tablespoons of milk until smooth. Add more milk for a thinner glaze or less for a thicker one. Drizzle over the top of the cooled cake.
2 cups powdered sugar, 1 teaspoon vanilla extract, ½ teaspoon ground cinnamon, 2-4 Tablespoons milk