In a mixing bowl, whisk together the flour, eggs, milk, melted butter, granulated sugar, and vanilla extract until smooth. Let the batter rest for 30 minutes.
Heat a non-stick skillet or crepe pan over medium heat. Lightly grease with butter. Pour about ¼ cup of batter into the pan, swirling to coat the bottom evenly. Cook for 1-2 minutes until the edges lift and the bottom is lightly golden. Flip and cook for another 1 minute. Transfer to a plate and repeat with the remaining batter.
In a bowl, mix softened cream cheese, powdered sugar, lemon juice, and lemon zest until well combined and smooth.
To assemble, spread a thin layer of the cream cheese mixture on half of a crepe, then sprinkle with fresh blueberries. Fold the crepe in half, then in half again to form a triangle. Serve warm.
Top with additional blueberries and a dollop of whipped cream if desired.