Preheat your oven to 350°F (175°C) and prepare a cupcake pan with liners.
In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition, and then stir in the vanilla extract.
In another bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry mixture to the wet ingredients, alternating with milk, starting and ending with the dry ingredients.
Spoon the batter into the prepared cupcake liners, filling each about two-thirds full.
Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center comes out clean.
Once baked, allow the cupcakes to cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely.
While cooling, prepare the frosting by beating together the powdered sugar, softened butter, and milk until smooth and fluffy. Add green food coloring to achieve the desired shade.
Pipe the green frosting onto the cooled cupcakes to resemble Christmas trees, using a star tip for a decorative effect.
Decorate the frosted cupcakes with edible ornaments and sprinkles to resemble Christmas decorations.