HEAT oven to 350°F. COMBINE egg whites, water and cream of tartar in large mixer bowl. BEAT on high speed until stiff but not dry, just until whites no longer slip when bowl is tilted.
BEAT egg yolks and salt in small mixer bowl on high speed until thick and lemon-colored. Gently but thoroughly FOLD yolks into whites.
HEAT butter in 10-inch nonstick omelet pan or skillet with ovenproof handle over medium-high heat until hot. POUR IN egg mixture; gently smooth surface. Reduce heat to medium. COOK until omelet is puffed and lightly browned on bottom, about 5 minutes. (Lift omelet at edge with spatula to judge color.)
PLACE pan in 350°F oven. BAKE until knife inserted halfway between center and outer edge comes out clean, 10 to 12 minutes. LOOSEN soufflé omelet edge with spatula. SERVE immediately.
For savory soufflé omelet: Fill with a combination of cheese, meat, seafood or poultry, and vegetables, as desired.
For sweet soufflé omelet: Substitute a pinch of sugar for the salt. Fill with preserves or fruit. Top with a dusting of powdered sugar or dessert sauce.
Insider Tips on How to Make a Perfect Soufflé Omelet
If pan handle is not ovenproof, wrap it completely in aluminum foil.
Puffy soufflé omelets begin to deflate when removed from oven, so plan to serve immediately.
To serve folded: Using sharp knife, cut across center of soufflé omelet, cutting through upper surface but not through to the bottom of soufflé omelet. Top with filling, if desired. Tip pan. Fold soufflé omelet in half with turner and invert onto warmed plate with a quick flip of the wrist. Cut in half or into quarters.
To serve open-faced: Invert pan over warmed plate, or slide omelet from pan onto plate. Top with filling, if desired. Cut in half or into quarters.
Keep the yolks separate from the whites. Fat from egg yolk will prevent egg whites from beating properly. When separating eggs, take care that no yolk gets in the whites. To avoid an accident, separate each egg white into a cup or small bowl before transferring it to the mixer bowl. Discard any white that has even a speck of yolk in it.
Equipment: Because any residue of fat on beaters or bowl will prevent egg whites from beating properly, they should be spotlessly clean. The bowl should be stainless steel or glass. Plastic bowls can retain a film of grease.
Egg temperature: It’s easiest to separate eggs cleanly when they are refrigerator cold. However egg whites whip to greater volume when they’ve had a chance to warm a bit, 20 to 30 minutes. Always start by separating the eggs first. Let the whites stand at room temperature while you prepare the dish, sauce and other ingredients.
Cream of tartar: The air beaten into egg whites can be lost quite easily. A small amount of acidic ingredient, such as cream of tartar, acts as a stabilizing agent. A bit of lemon juice or vinegar will also work.
Salt decreases egg-white foam stability, so it should be added to the other ingredients.
Beat egg whites just until they are stiff peaks but not dry and no longer slip when the bowl is tilted. When underbeaten, whites will not achieve full volume. Overbeaten whites form clumps of dry puffs that don’t hold air well, are difficult to incorporate when folding and do not expand properly when heated.
Gentle folding is the key to maintaining volume: Combining heavier mixtures with beaten egg whites can knock the air out of them. Begin by pouring the egg yolk mixture over the beaten whites, not vice versa. Then gradually and gently combine the mixtures by folding, rather than stirring. Using a rubber spatula, start with a downward stroke into the bowl, continue across the bottom, up the side and over the top of the mixture. Come up through the center every few strokes and rotate the bowl often as you fold. Fold just until the color of the mixture is uniform, with no streaks of white remaining.