You’ll need browned butter for both the streusel and the cake. You can brown the butter separately for each component, or you can brown the total amount all at once and then divide it. Browning everything at once saves time, but it requires a little more focus and careful measuring afterward. (See notes below on how to brown and divide the butter.)

In a medium bowl, mix the sugar, flour, salt, cinnamon, and vanilla. Stir in the cooled brown butter until crumbly, then fold in the pecans. Chill the streusel for 15 minutes while you prepare the cake.

Preheat oven to 350°F (177°C). Grease or line an 8x8-inch pan with parchment paper.

In a large bowl, beat the browned butter (113g) and sugar until smooth. Add the eggs, vanilla, pumpkin puree, and sour cream, mixing until combined.

In a separate bowl, whisk together the flour, baking powder, baking soda, salt, cinnamon, and pumpkin spice. Gently fold the dry ingredients into the wet mixture until just combined — don’t overmix.

Spread half of the batter into the prepared pan, sprinkle with half of the chilled streusel, then repeat with the remaining batter and the rest of the streusel.

Bake for 40–45 minutes, or until a toothpick inserted in the center comes out with moist crumbs. Cool the cake in the pan for 15 minutes, then lift it out and transfer to a wire rack to cool completely.

While the cake bakes, whisk together all the icing ingredients in a medium bowl until smooth. Drizzle the icing over the cooled cake. Optional: If doubling the icing, drizzle a little extra over each slice right before serving for an extra pop of salted maple flavor.