Preheat the oven to 350℉. Spray a 9x5-inch loaf pan with non-stick spray before lining with a piece of parchment paper the same width as the pan with the paper edges left to hang over the sides of the pan.

In a large mixing bowl, mix together the oil, brown sugar, eggs, sour cream, pumpkin puree, and vanilla until combined. In a separate bowl, whisk together the flour, baking powder, baking soda, salt, and spices. Add the dry ingredients to the wet and stir just until no streaks of flour remain. (A few lumps remaining are okay, do not overmix!)

Pour batter into the prepared pan and smooth into the edges and smooth the top. Bake in the preheated oven for 45-55 minutes or until a toothpick inserted into the center comes out clean. Let cool in the pan for 10 minutes before lifting out using the overhanging edges of parchment paper and placing on a wire rack to cool for at least 30 minutes before topping with the glaze.

In a small saucepan over medium heat, add the granulated sugar, milk, and butter. Bring to a boil for 2 minutes, stirring constantly. Remove from the heat and add the powdered sugar and vanilla and whisk until incorporated. Pour immediately over the slightly cooled down bread. Enjoy!