Ingredients:
1/2 cup (1 stick) unsalted butter, melted
1 cup granulated sugar
4 large eggs, separated
1/4 cup all-purpose flour
1/3 cup fresh lemon juice
1 tablespoon lemon zest (grated peel)
1 1/4 cups milk (preferably whole milk)
1/4 teaspoon salt
Powdered sugar for dusting (optional)