• Preheat your oven to 350°F (180°C) and grease an 8x8 square tin or line it with parchment paper for easy removal.

Streusel

• In a small bowl, mix together the butter, all-purpose flour, light brown sugar, granulated sugar, pumpkin pie spice, and kosher salt.
• Use a hand mixer or your hands to combine the ingredients until slightly crumbly, almost like a cookie dough texture. Set aside in the refrigerator while you prepare the pumpkin batter.
• It’s okay if it’s not crumbling perfectly right after mixing. This streusel is the slightest bit more hydrated than usual, but the butter will set in the fridge, allowing it to crumble beautifully by the time we need to use it.

Spiced sugar filling

• In a small bowl, mix together the sugar, flour, cinnamon, and pumpkin pie spice. Set aside.

Batter

• In a large mixing bowl, add pure pumpkin purée, granulated sugar, light brown sugar. Whisk. Then add melted salted butter, egg, and vanilla extract. Whisk everything together until smooth and fully combined.
• In the same bowl, whisk in the all-purpose flour, cake flour, baking powder, ground cinnamon, pumpkin pie spice, and Diamond Crystal kosher salt.
• Fold everything together just until combined.
• Pour half the pumpkin batter into the prepared cake tin and smooth the top.
• Add all of your spiced sugar filling evenly over your batter.
• Dollop the remaining batter all over the filling, then gently spread it into an even layer. Dolloping makes it easier to spread without dragging the filling up into the batter.
• Once you have a smooth top layer, remove the streusel topping from the fridge. Crumble it up with your fingers and evenly sprinkle it over the batter. Use all of it!
• Bake for 60-65 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.

Glaze

• While your cake is baking, in a small bowl, whisk together sifted powdered sugar, pumpkin pie spice, and whole milk. Be careful not to add too much milk, as you want a smooth, pourable consistency but not watery.

Back to our cake

• Allow the cake to cool in the pan for at least 20 minutes before gently lifting it out (using the parchment paper overhang if you lined your pan) and transferring it to a wire rack to cool completely.
• Once the coffee cake has cooled, drizzle the glaze evenly over the top. Allow the glaze to set before slicing and serving.