Preheat your oven to 400°F (200°C) and line a 6-inch springform pan with parchment paper, allowing the edges to rise above the rim.
Place the Greek yogurt, cottage cheese, egg, egg whites, honey, arrowroot powder, vanilla, lemon juice, and sea salt into a high-speed blender.
Blend on high until the mixture is completely smooth and contains no lumps from the cottage cheese.
Pour the batter into the prepared pan and tap it gently on the counter to release any large air bubbles.
Bake for 25 to 30 minutes until the top is dark brown and scorched, but the center still has a slight jiggle.
While the cheesecake bakes, combine the mixed berries and water in a small saucepan over medium heat.
Simmer the berries for 8 minutes, mashing them slightly with a fork until the liquid thickens into a coulis.
Remove the cheesecake from the oven and let it cool completely in the pan at room temperature.
Once cooled, refrigerate for at least 2 hours to set before slicing and serving with the berry coulis.