Preheat your oven to 325°F and lightly grease a small oven-safe baking dish or large ramekin.
In a mixing bowl, combine the ricotta cheese, Greek yogurt, whole egg, egg whites, maple syrup, vanilla extract, and sea salt.
Whisk the mixture vigorously until it is completely smooth and no lumps of ricotta remain.
In a small saucepan over medium heat, simmer the mixed berries and lemon juice for 5 minutes until the fruit bursts and the liquid thickens into a sauce.
Pour the creamy ricotta base into the prepared baking dish.
Drop spoonfuls of the berry sauce onto the top of the cheesecake and use a toothpick or knife to create a marbled swirl pattern.
Bake for 30 to 35 minutes until the edges are firm and the center is slightly set with a gentle wobble.
Remove from the oven and let it cool for at least 10 minutes to allow the texture to firm up before serving.