Make the Lemon Curd: In a saucepan, whisk together lemon juice, water, sugar, cornstarch, and turmeric. Heat over medium-low, stirring constantly until thickened and smooth. Remove from heat and let it cool to room temperature.
Prepare the Mousse: In a bowl, beat the heavy cream until soft peaks form. Add Greek yogurt, powdered sugar, and vanilla extract, then gently fold in the cooled lemon curd until fully combined.
Make the Raspberry Sauce: In a saucepan, combine raspberries, sugar, and lemon juice over medium heat. Cook until the raspberries break down and the sauce thickens slightly. Strain for a smoother texture if desired, then let it cool.
Assemble the Dessert: Spoon the lemon mousse into serving glasses, layering with raspberry sauce. Chill for at least 1 hour before serving for the best texture.
Serve & Enjoy: Garnish with fresh raspberries or a sprinkle of lemon zest for an elegant finish.