Warm up ½ cup cream in a microwave-safe bowl or a pot over a stovetop just until a simmer and not boiling. Add in the semi-sweet chocolate chips and cover the bowl with a lid/ dish. Keep it undisturbed for 30 seconds. The trapped heat of the cream will slowly start to melt the chocolate.
Now open the lid and start stirring gently. It will look goopy at first but after a minute of stirring, it will start to form a smooth chocolate sauce known as ganache.If you suspect that all the chocolate didn’t melt then just pop it in the microwave for 10 seconds at a time. Smoothen out the tiny bits of chocolate and keep the ganache aside to cool at room temperature.
Whipping chilled heavy whipping cream
Meanwhile in a big bowl add cream, a pinch of salt, and vanilla. Whip it with an electric or handheld whisk for 4-5 minutes. Or until you see that the cream has started to just thicken. Now switch off the electric whisk and just manually whisk it to a soft droopy peak consistency. Whisking with a hand, later on, gives you more control over the consistency and avoids over-whipping the cream.
We are looking for a very soft peak consistency. Please do not whisk until stiff peaks. The cream should be just thick and not hold the peaks at all.
Mixing process to make the mousse
The prepared chocolate mixture should have come to room temperature by now. It should not be warm. Now scoop 3-4 tablespoons already whipped cream into chocolate first. Fold it gently so that the cream is completely incorporated with chocolate. This is done to stabilize chocolate. It is a crucial step taken to avoid chocolate seizing when it comes in contact with chilled cream.
The next step is adding the chocolate mixture to the big bowl of already whipped cream. Fold it gently in one clockwise direction. We want the mouse light and fluffy. This way we are incorporating air in the mousse.
Once it is mixed well, transfer into an airtight container and refrigerate for 3-4 hours or overnight.
Whipping chilled heavy whipping cream
For whipping cream
Make sure the heavy whipping cream is well chilled in the refrigerator. Chill the whisk and the bowl in the freezer for 15 minutes.
Using a handheld mixer or a stand mixer fitted with a whisk attachment, whip the heavy cream, sugar, and vanilla extract on medium speed until 2 minutes.
Once the cream starts to thicken up, increase the speed to high until soft peaks form, about 1 minute. Now lower the speed and whisk until medium to stiff peaks form.
Be careful not to overwhip the cream or it will turn into butter.
One way to know that the cream is done is when you see deep streaks while whisking it. The whisk attachment should hold the cream in stiff peaks that do not drip or fall flat. Refrigerate until use.
For chocolate ganache drizzle
Place chopped chocolate or chocolate chips in a medium-sized heatproof bowl and set aside.
Pour heavy cream into a small saucepan and heat over medium heat just until cream comes to a simmer. You can warm up the cream in the microwave too.
Once cream is simmering, remove from heat and pour evenly over chocolate (do not stir). Cover with a lid and let sit for 5 minutes.
After 5 minutes, remove cover and use a whisk to gently whisk chocolate and cream together until completely melted and smooth. Use it to drizzle between the layers and the top of the trifle.
For assembling the trifle.
Cut the brownie into small cubes, depending on the size of the trifle cup. I prefer 4-5 oz cups.
Add a layer of brownie pieces on the bottom.
Spoon or pipe in the chocolate mousse.
Now add a big dollop of whipped cream using a spoon or a piping bag and spread it evenly.
Top it with a sprinkle of grated chocolate.
Repeat this process one more time with brownie, then mousse followed by a whipped cream layer and grated chocolate for garnish.
Notes
Possible substitutes
You can substitute every component with a store-bought one if desired.Swap my brownie recipe for boxed one or a chocolate cake sponge.Swap homemade whipped cream with cool whip topping.