Preheat oven to 400°F. Line a standard 12 cup muffin pan with paper liners and set aside.
Chop the cranberries, then add to a small mixing bowl. Add 2 Tbsp granulated sugar, stir, then set aside.
In a mixing bowl, add granulated sugar, light brown sugar, flour, baking powder, and salt. Whisk to combine. Set aside.
In another larger mixing bowl, add the egg, sour cream, and vegetable oil. Whisk together, then stir in the dry ingredients from the previous step, until just combined.
Gently stir in the cranberry mixture.
In the mixing bowl you used for the dry ingredients, add the crumble topping ingredients (flour, granulated sugar, brown sugar, and butter). Cut the butter into the mixture using a pastry cutter, two forks, or just your fingers. Once you get pea-sized clumps, you're good.
Scoop/pour batter into the prepared muffin pan, filling the liners about 2/3 of the way up. Evenly sprinkle the crumble topping over the tops of the muffin batter.
Bake in preheated oven for approximately 18 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs.
Remove muffin pan from oven and let muffins cool in the pan for a 3-5 minutes, then transfer to a wire cooling rack to continue cooling.