Chill a mixing bowl and beat together 1 cup cold heavy cream, 4 ounces softened cream cheese, and 2 tablespoons powdered sugar until soft peaks form, about 2–3 minutes; refrigerate while preparing other components.

Stir 1 cup plain Greek yogurt with 1 tablespoon maple syrup and 1 teaspoon vanilla, then fold in 3/4 cup of the stabilized whipped cream; layer crushed graham cracker (optional), chopped strawberries, the yogurt-cream, and blueberries in 4 small glasses, finishing with a dollop of whipped cream and a berry for garnish; chill.

Butter a 9×13-inch rimmed baking sheet; melt 3 tablespoons unsalted butter in a saucepan over low heat, add 10 ounces mini marshmallows and stir until melted; remove from heat and fold in 6 cups Rice Krispies cereal until coated, spread onto the sheet in an even 3/4-inch layer, and let rest 12–15 minutes until slightly firm; use a 2–2.5-inch star cutter to cut shapes and dust some with freeze-dried strawberry powder if desired; store at room temperature in an airtight container.

Spoon about 1 teaspoon lemon curd into the bottom of each of the 12 mini tart shells, then pipe or spoon the remaining stabilized whipped cream into each shell and top with blueberries and a small strawberry slice; chill at least 20 minutes before serving.

Arrange parfaits, Rice Krispie stars, and tartlets on a platter; keep chilled until serving for tartlets and parfaits, while keeping Rice Krispie stars at room temperature; store leftovers as noted in the article.