In a medium saucepan on low heat using a whisk mix together the lemon juice, sugar, lemon zest, and eggs.
Let it sit for 8 -10 minutes whisking occasionally. The mixture should be thickening.
Transfer the lemon mixture to a heatproof bowl. Cover with plastic wrap and chill in the refrigerator for 1 hour.
Using an electric hand mixer or standing mixer and a large bowl mix together the lemon mixture, heavy cream, and powdered sugar until peaks form.
You can leave the mousse in the bowl or divide it into dessert cups.
Let it chill in the refrigerator to set for 4 hours or overnight.
Top with blueberries or any kind of fruit or you can leave it as is (It still tastes amazing).