In a microwave safe bowl, heat 3/4 cup of heavy whipping cream until just below boiling (about a simmer). This is about 30-45 seconds.

Place chocolate chips in a large bowl and pour the hot heavy cream over the top. Cover with a towel and allow the mixture to sit about 5-7 minutes. Stir the mixture (I use a whisk but a rubber spatula will work too) until the chocolate is smooth and melted. Allow to sit for about 15-20 minutes, stirring occasionally.

In a separate bowl with a hand mixer, or in the bowl of a stand mixer, whisk 1 1/4 cups heavy whipping cream until soft peaks form.

Add in powdered sugar, vanilla extract, and espresso powder. Continue to whisk until stiff peaks form.

Reserve 1/2 cup of the whipped cream and refrigerate for serving. Gently fold the remaining whipped cream into the chocolate mixture, folding until all of the whipped cream is incorporated. (You want to do this as gently as possible to keep it as airy as possible).

Divide the mousse into 6 dishes (you can use ramekins, glasses, cups, or any dish you prefer). Chill in the fridge for at least 3-4 hours before serving.

When ready to serve, top with whipped cream and fresh berries. If desired, dust with cocoa powder or chocolate shavings (use a grater or vegetable peeler on a chocolate bar to make shavings).

Refrigerate all leftovers.