Preheat oven to 350F.

Microwave chopped chocolate in a small bowl on medium power for 1 minute; stir.

Microwave for another 2-2.5 minutes, stirring every 30 seconds, until melted.

Beat butter at medium speed with a stand mixer until creamy.

Gradually add granulated sugar and brown sugar, beating well.

Add egg yolks, one at a time, beating until blended after each addition.

Add melted chocolate and vanilla, beating at low speed until blended.

Sift cake flour, cocoa, baking powder, cinnamon, and salt in a medium bowl.

Add flour mixture to butter mixture alternately with milk, beginning and ending with flour mixture.

Beat at low speed until just blended after each addition.

Wash and dry beaters.

Beat egg whites at high speed until stiff peaks form.

Stir egg whites into batter in 3 batches.

Spoon batter into 3 greased and floured 9" round cake pans.

Bake at 350F for 30 minutes or until a wooden toothpick comes out clean.

Cool in pans on wire racks for 10 minutes; remove from pans to parchment paper-lined wire racks and cool completely (about 1 hour).

Cut cake into 1" cubes.

Layer one-third of cake cubes in a 4 qt bowl.

Top with one-third each of chocolate ganache and marshmallow topping.

Repeat layers twice.

For Chocolate Ganache: Microwave chopped semi-sweet and bittersweet chocolates with 1 1/2 cups heavy cream in a medium-sized bowl at medium power for 1 minute, stir.

Microwave for another 3-3.5 minutes or until melted, stirring every 30 seconds.

Stir in up to 1/4 cup cream, 1 tbsp at a time, until desired consistency.

Reserve 3/4 cup ganache to serve with trifle.

Reheat reserved chocolate ganache in a microwave-safe bowl at medium for 30-60 seconds, stirring every 30 seconds, just before serving.

For Marshmallow Topping: Beat marshmallow creme and 1 cup heavy cream at low speed of stand mixer for 1-1.5 minutes or until combined and smooth.

Add remaining heavy cream; beat at medium speed for 2 minutes or until light and fluffy.