Blend the strawberries until they are smooth using a blender or food processor. If you want, strain the puree through a fine sieve to remove the seeds.
Put the mashed strawberries in a bowl. Mix in the lemon juice, vanilla extract, and erythritol. Mix well.
Beat the thick cream and a pinch of salt in a big bowl until stiff peaks form.Carefully mix the strawberry mixture into the whipped cream until it is smooth and well combined.
Put the mousse into cups and refrigerate for at least one hour to firm up.
If you want, you can add a small mint leaf and some slices of fresh strawberry before serving.
Different types and recommendations
Use blueberries or raspberries instead of strawberries for a different flavor experience. Add more finely chopped nuts or unsweetened coconut flakes if you want to add some extra crunchiness. To make a richer mousse similar to cheesecake, softly mix melted cream cheese with the strawberries and then combine it with the whipped cream.