Step #1 Butter 4 soufflé dishes (1 1/4- to 1 1/2-c size) & dust with the parmesan cheese.
Step #2 In a 3- to 4-quart pan, mix milk with polenta & 3/4 tsp salt; add 1/4 c butter, cut into chunks.
Step #3 Stir over medium-high heat until mixture boils, then reduce heat to medium & stir until polenta is thick enough to hold a clean path for a few seconds when spoon is drawn across bottom of pan, 8 to 10 mins; remove this from heat.
Step #4 Meanwhile, whip egg whites until they hold distinct, with a mixer on high speed, In a large-ish bowl, moist peaks.
Step #5 Stir baking powder into polenta, then add egg yolks & stir this to mix well.
Step #6 Add about 1/4 of the egg whites & stir this to mix.
Step #7 Fold polenta mixture into remaining egg whites.
Step #8 Spoon batter equally into soufflé dishes.
Step #9 Set dishes slightly apart in a shallow 10- by 15-inch pan.
Step #10 Bake in 375° regular or convection oven until soufflés are well browned, 30 to 40 mins.
Step #11 Set each on a plate & mound lettuce leaves beside the dish.