Pour the heavy cream into a medium-sized microwave safe bowl and heat the cream for 30-45 seconds in the microwave, or until almost boiling. You can also heat until almost boiling on the stove using a small saucepan.
Remove the cream from heat and add the chocolate chips. Mix until the chocolate is melted and the mixture is smooth. Return to heat for a few seconds if needed to fully melt the chocolate.
Once the mixture is smooth, place the chocolate ganache in the fridge to begin cooling. Leave the mixture for 10-15 minutes total. Stir it after 5 minutes to ensure that it cools evenly.
Remove the chocolate from the fridge when it begins to feel cool to the touch – that means it's ready to whip into mousse! Take care not to leave it in the fridge for too long or the chocolate will begin to set.
Once the mixture is cool to the touch, remove it from the fridge and place it in a medium-large bowl or in a stand mixer bowl. I recommend using a stand mixer if you have it because the whipping process can take multiple minutes.
Whip the chocolate on medium-high speed using the whisk attachment. Mix until the mixture lightens and fluffs up. This will take 3-5 minutes.
Place the mousse in your desired serving bowl, then return it to the fridge to set. This will take 30-60 minutes.
