Clean the portobellos according to the previous pictorial "Portobello - Cleaning". Butterfly the mushroom by holding the knife parallel to the cutting board. Make a slice in the edge of mushroom into the center.

Rotate the knife towards yourself while turning the mushroom in the opposite direction. Go slowly so that the slice does not break in half.

Set up a three compartment breading station with seasoned flour, egg wash (milk and eggs) and breadcrumbs.

Dredge the slice in the flour and shake off any excess.

Submerge the slice in the egg wash. It is even more likely to break at this point so, handle with care.

Make sure all of the slice is covered in the wash. If there are spots where the flour shows through, it will not hold the breadcrumbs.

Press the slice into the breadcrumb mixture and carefully coat.

Turn the slice over and press again. Sprinkle crumbs on any bare spots.

Heat a large non-stick or well seasoned pan to medium high and then add a small amount of oil.

Add a tab butter. Adding butter after oil will prevent the butter from burning.

Just as the butter melts, add the breaded portobellos. Turn the heat down to medium to medium low.

Do not overcrowd the pan or they will not brown properly.

Brown slowly on one side and then flip over.

Brown well on the other side and then set aside on a sheet pan to warm. Wipe the pan free of crumbs and return to medium high heat.

Add the capers and saute for a couple of seconds. Add the white wine.

Add the lemon juice and reduce by half to make your sauce.

Once the liquid has reduced, whisk in the cold butter.

Turn the heat down to low so that the sauce will not break (separate). The sauce should be creamy and homogeneous. Season to taste.

Re-heat the mushrooms and then spoon the sauce over the top.