crumb topping 1 cup cold unsalted butter cubed 3/4 cup imperial sugarâ light brown sugarâ  1/2 teaspoon kosher salt1 teaspoon cinnamon1 cup all-purpose flour* cinnamon swirl 1/2 cup imperial sugar extra fine granulated sugar1 1/2â teaspoons cinnamon cake 1 cup unsalted butter, room temperature1 1/