To make the streusel, combine flour, and sugar in a small bowl, mix together thoroughly with a whisk. Cut the cold butter into small cubes and add to the dry mixture. Use a pastry blender to cut the butter into the dry mixture until coarse crumbs form. Cover and refrigerate until ready to use.

Preheat oven to 350°F.

Brush a loaf pan with melted butter and line the bottom with a piece of parchment paper, letting the excess hang over the sides. Brush the parchment paper with more butter. Set aside.

In a medium mixing bowl, add sugar and orange zest, rub together with your fingers or mix with a whisk to release the oil. Sift in the flour, baking soda and baking powder. Add the kosher salt and whisk the mixture until evenly distributed. Toss the cranberries in the flour mixture, and set aside.

Add sour cream, eggs, oil, and vanilla extract to a large mixing bowl and beat together with a hand whisk until smooth. Add the flour mixture and fold with a spatula until just incorporated with a few streaks of flour remaining.

Transfer the batter to the prepared loaf pan, sprinkle the streusel evenly over the top, and bake for 55 - 65 minutes until a toothpick inserted in the center of the loaf comes out clean with just a few crumbs attached, but no wet batter.

Allow the bread to cool in the pan for 5 - 10 minutes before removing it from the pan and let it cool further on a wire rack. Best served slightly warm.