Instructions

• Preheat oven to 350°F (177°C). Grease and lightly flour a 9-inch square baking pan. Set aside.
• Whisk together the flour, baking powder, baking soda, pumpkin pie spice, and salt in a medium bowl. Set aside.
• In a large bowl, beat the butter, granulated sugar, and brown sugar together until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla extract. Scrape down the sides and bottom of the bowl as needed.
• With the mixer on low speed, gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Beat until just combined. Stir in the pumpkin puree.
• Pour the batter into the prepared baking pan and spread evenly.
• Make the streusel: Combine the flour, brown sugar, and cinnamon in a small bowl. Pour the melted butter over the mixture and stir until crumbly.
• Sprinkle the streusel evenly over the batter.
• Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.
• Let cool completely before cutting into squares and serving.