Chocolate three ways is the nicest way to end a meal!
Preheat oven to 350 degrees Fahrenheit. Line a quarter sheet pan with parchment paper.
Melt the chocolate and margarine over a double boiler or in the microwave.
Whisk together the egg yolks and the confectioners’ sugar until smooth and creamy. Fold in the sifted flour. Add the melted chocolate to the egg mixture and whisk to incorporate.
Pour batter into the sheet pan and spread to even out batter. Tap pan on the counter to pop the air bubbles. Bake for 10 minutes – it should still be wobbly in the center. Take it out and cool on wire cooling rack. Place in fridge to firm up.
Heat the whipped topping and coffee in a small saucepan until bubbles form around the rim.
Place chopped chocolate in a bowl. Pour topping mixture over the chopped chocolate and let sit one minute to melt the chocolate. Whisk until smooth. Add liquor. You can use an immersion blender to achieve a smooth consistency. Let cool at room temperature to firm up.
Place mousse in mixer and beat for one minute until fluffy.
Put mousse in a piping bag fitted with a large round tip, such as 805 or 2A.
Using a marker, make 1-and-3/4-inch by 4-inch rectangles on a sheet of paper and place beneath the acetate sheet.
Melt the chopped chocolate in a double boiler until smooth. Place in a disposable piping bag and snip a tiny hole at the tip. Drizzle chocolate in a random pattern to mostly fill the rectangle template. Let set in the fridge.
Remove cake from refrigerator. Use the parchment to flip over on to a clean work surface.
Remove the parchment paper and trim the edges to straighten out. Cut vertically into four strips measuring one and three-fourths inches wide. Cut each strip in three to achieve rectangles measuring four inches long. You should yield (12) 1-and-3/4-inch by 4-inch rectangles.
Pipe eight to 10 beads of mocha mousse on top of each brownie and top with chocolate garnish. Dab a few dots of gold leaf on the chocolate using the tip of a knife.
Serve or freeze in an airtight container.