Add the erythritol to a small bowl. Zest the lemon and orange and mix them with the sweetener for a couple of minutes. Squeeze out the lemon and add the juice to the bowl with the sweetener and zest.
Step 2
Add the heavy cream to another bowl. Beat using a hand mixer until light and fluffy. Add the contents of the other bowl and lemon extract to the whipped cream. Beat for 30 seconds until incorporated.
Step 3
Divide the mousse into small dessert glasses or bowls. Garnish with lemon and orange zest. Serve immediately or transfer to the fridge to chill.