Preheat your oven to 350 degrees, and line a muffin tin with cupcake liners.
In a medium bowl, whisk together flour, baking powder, and salt. Set aside.
In a large bowl, mix together butter and sugar for 1-2 minutes, until light and fluffy.
Add eggs, vanilla, and sour cream, mix again until just combined.
Spoon the cupcake batter into the cupcake liners, fill them a little over ½ way full.
Bake 17-18 minutes, until a toothpick inserted in the center comes out clean.
Meanwhile, in a large bowl, mix together cream cheese, butter, vanilla, and food coloring.
Slowly add powdered sugar, mixing well to combine.
Mix in additional green food coloring, if needed to reach desired shade of green frosting.
Once the cupcakes are cooled, frost them generously creating your tree shape as you go up.
Top with a star sprinkle and additional red, white, and green nonpareils.