Preheat oven to 350 degrees. Grease and flour the bottom and sides of a 9 x 5 loaf pan and set aside.
Add flour, baking powder, baking soda and salt to a large mixing bowl. Whisk to combine then set aside.
In a separate bowl, whisk brown sugar, granulated sugar, oil, eggs, sour cream, vanilla, milk, orange juice and orange zest until well combined. Set aside.
Add dry ingredients to wet then stir with a wooden spoon until just moistened and flour is still visible. Do not overmix.
In a small bowl, toss 1 cup of cranberries with 1 Tablespoon of flour until berries are coated to prevent sinking while baking.
Gently fold floured cranberries into the batter then stir until evenly distributed.
Pour batter into prepared baking pan and top with remaining 1/4 cup of fresh cranberries.
Bake for 50 to 55 minutes, covering the top with aluminum foil after the first 30 minutes to prevent overbrowning. Loaf is done when a toothpick inserted into the center comes out clean.
Remove bread from oven and cool in the pan for 10 minutes then turn out onto a wire rack to cool completely.
Dust loaf with powdered sugar then slice and serve.
Store leftovers in an airtight container at room temperature up to 3 days.