• Preheat oven to 350℉ / 177℃
• Prepare an 8-inch round cake pan by coating with baking spray and lining the bottom with parchment paper.

Cake

• Place chocolate and butter in a heat-resistant bowl. Microwave on 50% power for 30 seconds and stir briefly. Continue to heat at 30 second intervals, stirring between each heating, until butter and chocolate are melted.
• Add sugar, salt and vanilla to the bowl with melted chocolate/butter. Whisk until well blended.
• Add eggs. Whisk until well blended.
• Add cocoa powder and whisk until well blended.
• Pour cake batter into the prepared cake pan. Smooth top with an offset spatula or by tapping lightly on a countertop.
• Bake for 25 - 30 minutes in pre-heated oven. The cake is finished when the internal temperature of the cake is 200℉ / 94℃ (use an instant read thermometer inserted into the center of the cake to check for doneness).
• Place the cake on a wire rack for 10 minutes. Run an offset spatula around the inside of the cake pan and flip over onto a wire rack. Let the cake cool completely
• Optional: sprinkle a few tablespoons of powdered sugar over top of cake before decorating.

Royal Icing

• Place all ingredients (powdered sugar, warm water and meringue powder) in the bowl of a hand or stand mixer. Begin mixing on low speed and gradually increase speed to medium high. Mix for 3 - 4 minutes.
• Divide the royal icing evenly into three bowls. Leave one portion white, then color the other two portions red and green. Cover bowls with damp kitchen towels to prevent icing from drying out.

Decorating

• Cut cake into 8 equally sized portions.
• Place green and red royal icing into pastry bags fitted with a small round tip. Place white royal icing into a pastry bag fitted with a small star tip.
• Christmas tree using green icing: Hold the piping bag about half an inch off the surface. Squeeze the bag gently while moving it in a wavy motion, starting with narrow lines at the top and gradually widening them as you move downward to form the tree's shape. While the icing is still wet, add sprinkles for ornaments
• Santa hat using red icing: Hold the piping bag about half an inch off the surface. Squeeze the bag gently while moving it in a wavy motion, starting with narrow lines at the top and gradually widening them as you move downward to form the hat's shape.
• Once the red icing is in place, use white icing to pipe a fluffy fur trim at the base of the hat and a pompom at the tip.
• Allow the decorated cake to rest for one hour to ensure the decorations have time to dry and set properly.