Oven pre-heated to 350F. Prep jellyroll pan with parchment paper.
Using mixer, beat butter until creamy.
Add sugar & oil until combined.
Next add in vanilla extract.
In separate bowl, whisk together flour, baking powder, and salt.
Alternating between the flour mixture/milk, add to your buttermixture ending with the flour. Combining completely before addingmore.
Combine egg whites in a separate bowl, mixing on high until stiffpeaks form.
Fold in egg whites into batter gently.
Pour batter into jellyroll pan; spreading evenly.
Bake at 350F for approx 15 mins. Toothpick should come out clean.
Cool for 15 mins. Transfer to cooling rack to cool completely.
Cut out even number of trees.
Sandwich with frosting.
Pour melted white chocolate over trees on wire rack.
Drizzle red melted chocolate and top with green sugar sprinkles
Let cool and harden.