Preheat and prepare pan. Position a rack in the center of your oven and preheat the oven to 350°F (177°C). Spray a 9”x5” loaf pan with cooking spray, or line with parchment paper and then spray with cooking spray.
Make the streusel. In a small mixing bowl, stir together the sugars, flour, cinnamon, salt and walnuts. Stir in melted butter until a crumbly mixture is formed. Set aside. ¼ cup (50 g) granulated sugar ¼ cup (57 g) packed light brown sugar ¼ cup (30 g) all-purpose flour ½ teaspoon cinnamon Pinch salt ¼ cup (28 g) chopped, toasted walnuts 4 Tablespoons (¼ cup, 57 g) unsalted butter, melted
Combine dry ingredients. In a mixing bowl, whisk together all-purpose flour, brown sugar, baking powder, cinnamon, and salt. Set aside. 2 cups (240 g) all-purpose flour 1 cup (213 g) packed light brown sugar 1 tablespoon baking powder 1 ½ teaspoons cinnamon ¼ teaspoon salt
Combine wet ingredients. In a second mixing bowl, whisk together eggs, milk, sour cream oil and vanilla. 2 large eggs ⅓ cup (80 ml) milk ⅓ cup (76 g) sour cream ½ cup (120 ml) neutral-flavored oil (vegetable, canola, grapeseed, or safflower) 1 teaspoon vanilla extract
Combine wet and dry ingredients. Add the dry ingredients to the wet ingredients and mix together with a spatula or wooden spoon just until just combined. Fold in chopped walnuts. Do not overmix. 1 cup (113 g) chopped, toasted walnuts
Bake. Spoon ½ of the batter into prepared loaf pan. Sprinkle on ½ of the streusel. Spoon the rest of the batter on top. Sprinkle on remaining streusel. Bake in a preheated 350°F (177°C) oven for 60-70 minutes until a toothpick inserted into the middle of bread comes out clean or with a few moist crumbs clinging to it (no wet batter) and top springs back to the touch when lightly touched. Remove from the oven and cool completely in the pan on a wire cooling rack.
Make the glaze. In a small bowl, whisk together the glaze ingredients, and drizzle over the cooled bread. 1 cup (113 g) confectioners sugar 2-3 Tablespoons Milk ½ teaspoon vanilla extract