The Best Pumpkin Coffee Cake

Ingredients

• 2 1/4 cups all-purpose flour
• 1 1/4 teaspoons baking powder
• 1 teaspoon baking soda
• 1/2 teaspoon salt
• 2 1/2 teaspoons pumpkin pie spice
• 1/2 cup brown sugar
• 1 cup granulated sugar
• 2 teaspoons pure vanilla extract
• 1 cup pumpkin puree
• 2 large eggs
• 1/2 cup vegetable oil
• 3/4 cup buttermilk
• 1/3 cup packed brown sugar
• 1/3 cup granulated sugar
• 1 teaspoon ground cinnamon
• 3/4 cup graham cracker crumbs
• 3/4 cup all-purpose flour
• 1/2 cup plus 2 tablespoons unsalted butter, melted