I came up with this over a year ago, and it may seem pretty obvious, but I didn't find any mention of it here. I just had this today, and it's so good I figured I'd add it for anyone else looking for a nice LC version of Egg McMuffins.

Per muffin:
2 large portobello caps, washed and dried
1 egg

Toppings:
cheddar cheese
bacon or ham or sausage patty
whatever else you like

This is, as you'll see, easiest with a toaster oven. Toast the caps for about a minute or a minute and a half. Remove one cap, toast the other cap with cheese on it until it's melted. I suppose you could nuke it, but we don't have a microwave, so use your own judgement.

Meanwhile, beat and cook the egg in a small pan over low-med heat. Fold it up (kind of like an omelette) when it's almost cooked through. Mine always turn out kind of squarish. Place egg on other cap when cooked.

Also prepare your bacon or whatever else (that pre-cooked bacon is wonderfully convenient, but I've also just warmed up ham in the egg pan (once the egg was taken out).

Sandwich it together, and enjoy! I get about 5g carbs minus 1g fibre from this, so it's even suitable for induction.

I know it may sound like a lot of work, but really it isn't. This shouldn't take more than about 10 minutes, even if you're being elaborate about it.

a friend of mine uses the portabella mushroom caps as pizza crust. i've never tried it but it sure sounds yummy!

Yeah, they work great for pizza! And they're individually sized, so each person can have one or two with their own favourite toppings.

now why the heck didn't I thnk of that! I love portos, always used them "in" sandwiches but never "as" sandwiches! Paradigm shift in progress.

Hey... that's a great idea for that dish with the sauce that goes over an egg, ham and english muffin, just use a giant mushroom instead. What's that called? Can't think of it...

Oh yeah! Eggs Benedict.