Process cottage cheese, cream cheese, sugar and vanilla together in a food processor or blender (or you can stir by hand) until well-blended. Set aside.
Whisk together flour, salt, milk, eggs and 2 tablespoons of the butter until combined. Refrigerate mixture for at least 15 minutes, but preferably at least 1 hour.
Heat 1 tablespoon of the remaining butter in a small (preferably non-stick) skillet over medium-high heat. Add about 1/4-cup of the batter, and immediately swirl the pan so that the batter spreads to make a large, thin circle of batter on the bottom of the pan.
Cook for 15-25 seconds on the first side until you can slide a spatula underneath to flip the crepe. Then flip and cook for an additional 15 seconds until done. Remove and set aside. Repeat with remaining batter.
Fill each crepe with about 2 Tbsp. of the cheese filling, and 1/3-cup of sliced bananas. Then fold the bottom side of the crepe over the bananas, fold in the two left and right sides, and then roll the crepe over the top side until a little pouch is formed. Repeat with remaining crepes and bananas.
Heat the remaining 1 tablespoon of butter over medium-high heat. Then add the blintzes - 2 at a time - to the pan, and brown on all sides.
Serve dusted with powdered sugar, and drizzled with warm caramel sauce. Then sprinkle each blintz with a tiny pinch of sea salt.
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