In a large bowl whisk together 2 cups flour, ½ teaspoon baking powder, ½ teaspoon baking soda, and ½ teaspoon salt. Set aside.
In a large bowl, beat together 1 cup butter and 1 ¼ cup sugar, until light and fluffy (about 3-4 minutes). Add ½ cup sour cream and beat until incorporated. Beat in 4 eggs, 1 at a time. Add in 4 teaspoons vanilla extract and beat until combined.
Add the flour mixture all at once and beat on low until just combined. Add the food coloring and fold until just combined. Scrape the batter into a prepared 9x5x3-inch pan loaf pan and smooth out the top. Bake for 60 to 65 minutes.
Remove from the oven and transfer to a wire rack to cool completely.
Remove the cake and slice the loaf into 1/2 inch pieces. Using a Christmas tree cookie cutter, stamp out the trees. Stack one cut-out tree on top of another to form a large log shape. Carefully wrap with plastic wrap and transfer to the refrigerator to chill (this will make it easier to handle).
Heat the oven to 325 degrees again.
In a large bowl whisk together, flour, baking powder, baking soda, and salt. Set aside. In a large bowl whisk together 2 cups flour, ½ teaspoon baking powder, ½ teaspoon baking soda and ½ teaspoon salt. Set aside.
In a large bowl, beat together 1 cup butter and 1 ¼ cup sugar, until light and fluffy (about 3-4 minutes). Add ½ cup sour cream and beat until incorporated. Beat in 4 eggs, 1 at a time. Add in 4 teaspoons vanilla extract and beat until combined.
Add the flour mixture all at once and beat on low until just combined. Add the Christmas confetti and very gently fold to combine.
Pour 1/4 of the batter into a prepared 9x5x3-inch pan loaf pan. Gently place the Christmas tree cake cut out into the pan.
Pour the remaining batter around it. Bake for 60-65 minutes. Remove from the oven and transfer to a wire rack to cool completely.
Trim the top of cake to an even finish. Cover with the frosting and sprinkle with the Christmas sprinkles.