Preheat your oven to 325°F and prepare a 9x13 pan by lining it with parchment paper.
In a medium-sized bowl, whisk together 2 cups of all-purpose flour, 1 1/4 teaspoons of salt, and 2 teaspoons of baking powder. Set this dry mixture aside.
In a larger bowl, beat 4 large eggs, 1 3/4 cups of granulated sugar, 1 1/2 teaspoons of vanilla extract, and 1 1/2 teaspoons of orange (or almond or more vanilla) extract. Beat until the mixture is thick and pale.
In a saucepan, heat 1 cup of milk and 1 tablespoon of orange zest until small bubbles appear. Remove it from heat, stir in 1/4 cup of unsalted butter and 1/3 cup of oil until melted. Slowly add this mixture to the egg mixture.
Gradually fold the dry ingredients into the wet ingredients until just combined. Transfer the batter to the pan that has been prepared.
Bake for 38-40 minutes or until a toothpick comes out clean. Let the cake cool thoroughly on a wire rack.
For the buttercream, cream together 1 lb of unsalted butter, 1.5 lb of confectioners’ sugar, 1 tsp of vanilla extract, and a pinch of salt. Adjust the consistency with 1-2 tbsp of heavy whipping cream if needed. Divide the buttercream, adding green food coloring to one batch.
Cut out a large triangle from the cake and arrange the cut-offs into a second triangle. Frost the assembled cake with chocolate fudge frosting.
Frost the sides and top with the green buttercream and sprinkle with green sanding sprinkles.
Cut a star from the bottom and attach it to the top with an ice cream cone frosted in brown as the tree trunk.
Decorate the cake with red lines using decorating icing. Your festive Christmas Tree Cake is ready to be enjoyed.