Coat 8 (6-ounce) ramekins or custard cups with cooking spray; sprinkle with 2 tablespoons granulated sugar. Place prepared ramekins on a baking sheet.
Lightly spoon flour into a dry measuring cup, and level with a knife. Place flour in a small saucepan. Gradually add milk, stirring with a whisk until well-blended. Stir in the lemon rind, lemon juice, and 1/4 cup granulated sugar. Cook lemon mixture over medium heat until thick and bubbly (about 5 minutes), stirring constantly. Gradually add hot milk mixture to egg yolks, stirring constantly with a whisk. Return the milk mixture to the pan, and cook over medium heat until thick (about 3 minutes), stirring constantly. Remove from heat. Place pan in a large ice-filled bowl for 25 minutes or until custard comes to room temperature, stirring occasionally.
Preheat oven to 400°.
Beat the egg whites, cream of tartar, and salt at high speed of a mixer until soft peaks form. Gradually add 1/3 cup granulated sugar, 1 tablespoon at a time, beating the egg white mixture until stiff peaks form. Gently fold one-fourth of the egg white mixture into the lemon mixture, and gently fold in the remaining egg white mixture. Spoon mixture into prepared ramekins.
Bake at 400° for 20 minutes or until the soufflés are puffy and set. Heat Lemon Curd in a small saucepan over low heat until warm. Spoon 1 tablespoon Lemon Curd into each soufflé, and sprinkle each with 2 teaspoons powdered sugar. Serve immediately.