Add the full-fat cottage cheese, natural peanut butter, PB2 powder, vanilla protein powder, maple syrup, vanilla bean paste, and a pinch of kosher salt to a high-speed blender or food processor.
Blend the mixture continuously for 1 to 2 minutes until it becomes completely smooth, creamy, and free of any lumps, scraping down the sides of the bowl with a spatula as needed. Taste the mixture and adjust the sweetness with a bit more maple syrup if desired.
Divide the smooth cream evenly among 4 small jars, ramekins, or dessert cups. Place the cups into the refrigerator to chill for at least a few hours to thicken up and set properly.
Melt the chopped dark chocolate and the optional coconut oil together in the microwave in short bursts, stirring frequently until completely smooth.
Spoon a thin, even layer of the melted chocolate over the top of each chilled mousse cup, gently spreading it all the way to the edges to seal it. Sprinkle the wet chocolate lightly with a pinch of flaky sea salt.
Return the dessert cups to the refrigerator for 10 to 15 minutes, or until the chocolate top is completely set and firm to the touch, then serve immediately.