Cake:
2 cups all-purpose flour
2 teaspoons baking powder
1/2 teaspoon baking soda
1/2 teaspoon kosher salt
1/4 teaspoon ground ginger
1/4 teaspoon cardamom
1/4 teaspoon freshly grated nutmeg
1/2 cup plus 2 tablespoons unsalted butter, room temperature
1 1/2 cups granulated sugar
2 eggs
1 1/2 cups pumpkin butter
Grated zest of 1 orange
Glaze and topping:
2 cups powdered sugar
Juice of 1 orange
Roasted pumpkin seeds, optional
Heat oven to 350F. Spray a 10-cup Bundt pan with baking spray. Stir together dry ingredients. In a large bowl beat together butter and sugar on medium until smooth. Add eggs one at a time, scraping the bowl down between each addition. Add pumpkin butter, zest, and ginger and mix on low speed until blended. Stir in flour mixture. Pour batter into prepared pan and smooth top with a spatula.
Bake until a tester comes out clean, 45 to 50 minutes. Let cake cool completely before glazing. Turn cool cake out of pan onto a rack. In a small bowl, whisk together glaze ingredients. Drizzle over cake and sprinkle with pumpkin seeds, if using.