Make the streusel topping by combining flour, brown sugar, cinnamon, and butter in a medium bowl. Blend together well until it looks like damp crumbs. Reserve the pecans for later and set aside.

Make the cinnamon swirl by combining all ingredients until evenly blended.

Preheat your oven to 350 degrees F and line a 9x5-inch loaf pan with parchment paper.

Make the pumpkin batter by combining pumpkin puree, melted butter, both sugars, vanilla, and eggs in a large bowl. Whisk to blend well.

Sift together flour, baking powder, baking soda, pumpkin spice, and salt. Whisk to blend evenly and add it to the wet mixture, folding it in gently. Before all of the flour is incorporated, add the milk and continue to fold gently until evenly combined.

Scrape one-third of the batter into the prepared pan and spread it out evenly. Sprinkle half of the cinnamon sugar mixture (about 2 ? tbsp) evenly over the surface. Spoon half of the remaining batter (another third of the batter) over the cinnamon sugar and gently spread it out.

Spoon the rest of the batter over the cinnamon sugar and spread it out evenly. Sprinkle half of the crumble over the surface, then scatter the pecans on top. Finally, sprinkle on the rest of the crumble.

Bake for 50-60 minutes until it feels firm in the middle and a skewer inserted into the center comes out clean. Allow the loaf to cool for 20 minutes in the pan, then lift it out using the overhanging parchment paper and let it finish cooling on a wire rack.

Make the maple glaze by combining all ingredients in a small bowl and whisking until smooth. Drizzle it over the cooled loaf and let set for a few minutes before slicing.