Step 1: Preheat your oven to 350°F (175°C). In a large mixing bowl, combine 1 cup of granulated sugar, 1/3 cup of unsweetened cocoa powder, and 1/8 teaspoon of salt. Whisk together until well blended. Add in the 1/2 cup of melted butter, 1/2 teaspoon of vanilla, and 2 beaten eggs. Mix until combined.
Step 2: Gradually stir in 1 1/2 cups + 2 tablespoons of all-purpose flour and 1/2 cup of semi-sweet chocolate chips until just combined. Be careful not to overmix.
Step 3: Pour the batter into a greased 9x9 inch baking pan. Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely before cutting it into small squares.
Step 4: In a medium bowl, use an electric mixer to beat the 8 ounces of softened cream cheese and 3 tablespoons of granulated sugar until smooth. In a double boiler or microwave, melt 4 ounces of chopped semi-sweet baking chocolate and let it cool slightly. Gradually fold the melted chocolate into the cream cheese mixture until fully combined.
Step 5: In another bowl, whip 1 1/2 cups of heavy whipping cream until stiff peaks form. Gently fold the whipped cream into the cream cheese and chocolate mixture until well incorporated.
Step 6: In your trifle cups or small glasses, start with a layer of chocolate cake squares. Follow this with a layer of the cream cheese mixture, then another layer of cake, and finish with a layer of whipped cream. Repeat the layers until your cups are full, ending with whipped cream on top.
Step 7: To finish, drizzle chocolate syrup over the top of each trifle. You can also add chocolate shavings or extra chocolate chips for decoration if desired.