Very rich, totally delicious. I used my immersible blender, would have been easier with standard blender, dusted pan with parm as contributor suggested. Filled the house with the most tantalizing aromas while baking and we weren't a bit disappointed when it finally emerged from the oven--it was terrific! I had made it with 7 eggs rather than 5, so adjusted the other ingredients to a bit less than one and a half extra. Baked it in a Corningware French White casserole dish with straight sides because didn't have large enough soufflé dish, it puffed nicely. The browned top, sides and bottom tasted so good I thought I'd died and gone to heaven. Easy as can be, readily available ingredients, tastes and looks good enough to serve at a party, and virtually no carbs. Who could ask for more? This one's a winner for sure!
It looked beautiful (photo in Fiestaware bread pan), then it fell. I sort of expected that as it lacks flour, but that's the whole point isn't it. Low Carb, no gluten, fast and easy to assemble. Despite falling it was still fairly light and fluffy and absolutely delicious. Will make again. Perhaps next time with a little more mustard.
When I read this recipe I thought it would turn out more like a baked omelet than a classic soufflé. I was wrong. It did not puff up quite as high as a classic soufflé, and was not quite as light, but it was very close and had great flavor with a beautiful texture. What a wonderful and delicious way to save both time and effort.