Preheat oven to 350 degrees. Butter 4 6-ounce souffle dishes, and then dust with granulated sugar.
In a small saucepan whisk together yolks, flour, juice, zest, milk and 1 tablespoon granulated sugar. Continue whisking on medium-low heat until mixture thickens, 3-4 minutes. Strain through a sieve and refrigerate to let cool.
Beat whites and cream of tartar until foamy. Gradually add remaining 2 tablespoons sugar, and beat until stiff peaks form.
Stir ¼ of the whites into the yolk mixture to lighten it. Gently fold in the remaining whites using a rubber spatula taking care not to deflate
Fill each souffle dish to the top and level. Wipe any excess batter from the rims
Bake until souffles rise and are golden and set, about 15-20 minutes. Remove from oven, dust with powdered sugar, garnish if desired, and serve immediately.
I am not a health professional and nutrition data is calculated programatically. Accuracy may vary with product selection, calculator accuracy, etc. Consult a professional for the best information.