Preheat oven to 350°F. Butter a 9x13 baking dish.

In the bowl of a stand mixer, beat the butter and sugars together until light and fluffy. Beat in the eggs. Stir in the pumpkin puree. Add flour mixture and stir until just combined.

To make the cinnamon swirl, add the brown sugar, butter, and cinnamon to a small saucepan over medium heat and stir constantly until melted.

Spread half of batter in prepared baking pan. Pour half of the cinnamon swirl over the batter and drag a knife through the batter to swirl it around. Top with the remaining batter and repeat with the remaining cinnamon swirl mixture.

To make the crumb topping, add flour, butter, brown sugar, and cinnamon to a medium bowl and cut together with a pastry cutter or two butter knives until you have coarse crumbs.

Sprinkle with the crumb topping.

Bake coffee cake until toothpick inserted in center comes out clean, about 45 minutes. Cool 30 minutes before glazing and serving.

To make the glaze, whisk together the powdered sugar and milk or cream until smooth.

Store leftovers in the refrigerator.