Know this
The orange is a parasite. It colonizes a russula or a milk cap, stops its growth, and coats the whole thing in a hard orange crust that smells faintly of shellfish. What you buy is the two of them fused into one body. It cooks dense and snappy, closer to scallop than to portobello, which is where the name comes from. Buy firm ones with bright orange skin and no soft dark patches, from someone who knows their supplier. Chef secret: they are almost always gritty. Cut them first, then swirl the pieces in a bowl of water and lift them out with your hands. Pour the bowl off and the sand goes right back on.
Cook
Dry sear in a hot pan until the edges take color, then butter, garlic and a squeeze of lemon. No crowding, or they steam.
Season
August into October, right after the late summer rains.
Best pairings
butter · garlic · lemon · thyme · cream · shallot
Also worth trying: white wine, parsley, leek, sherry, chives, black pepper, tarragon, creme fraiche, bacon, corn.
Recommended wine
An unoaked white with some body, like Chardonnay or a dry Riesling. Around $18 to $30.
See the full pairing guide