In a small saucepan over medium heat, combine the chopped rhubarb, sugar, and water. Stir continuously until it reaches a gentle boil, about 3–5 minutes. Reduce heat and simmer uncovered for 10 minutes until tender.

Remove from heat and let the rhubarb mixture cool to room temperature, stirring occasionally.

While the rhubarb cools, rinse and slice the fresh strawberries. Blend them with remaining sugar in a food processor until smooth, about 1–2 minutes.

Gently stir the strawberry puree into the cooled rhubarb mixture until well combined.

Whip the heavy cream in a separate bowl until soft peaks form. Fold the whipped cream into the strawberry and rhubarb mixture gently.

Spoon the final mixture into dessert glasses. Cover and refrigerate for at least 2 hours before serving, garnished with fresh strawberry slices.