In a blender, combine the eggs, milk, flour, sugar, and salt. Blend until the mixture forms a smooth batter. Preheat a 10-inch nonstick crepe pan or skillet over medium low-heat. Melt 1 cube of butter in the pan. Add 1/4 cup of batter and quickly tilt the pan to form an even coating of batter on the bottom of the pan. Cook until set and slightly browned, about 1 minute. Using a heat-resistant spatula, carefully loosen the sides and gently flip the crepe over. Cook for 1 minute. Repeat with the remaining butter and batter.

Add 1 tablespoon of peanut butter to each crepe and, using the back of a spoon, spread evenly over the crepes leaving a 1/2-inch border. Spread 1 to 2 teaspoons of jam over the peanut butter. Line 5 to 6 blueberries along the center of each crepe. Fold the crepe in half over the blueberries. Fold the 2 ends inward and continue to roll into a tube shape. Repeat with remaining ingredients. Cut each crepe in half horizontally and arrange on a platter. Dust with powdered sugar and serve.