Place the gelatin sheets in a bowl with cold water for 5 minutes.

Place the strawberries, sugar, and lemon juice into a saucepan and purée using an immersion blender. You can also use a stand blender and then transfer the mixture into a saucepan.

When the gelatin has bloomed, squeeze the sheets to remove as much water as possible. Add the gelatin to the strawberry mixture and place the saucepan over medium heat.

Heat the mixture just until the gelatin sheets have completely dissolved. The end mixture should be warm, not hot. Do not bring the mixture to a simmer. When done, set aside to cool down until thickened but not set.

Whip the heavy whipping cream to soft peaks. Do not overwhip!

Pour the strawberry mixture through a fine sieve into the whipping cream.

Fold with a rubber spatula to a homogenous consistency.

Pour the final mixture into 4 standard-size ramekins or any other molds of your choice and refrigerate until set. Can take 2-4 hours. You can also freeze the mousse until set to speed up the prosses. Decorate with fresh strawberries or whipped cream before serving.