Mix the olive oil with the herbs and some black pepper, and brush it liberally on both sides of the mushroom. Heat a heavy-bottomed 8-inch non-stick skillet over high heat and, when hot, sprinkle the surface lightly with salt. Add the mushroom to the hot pan and cook, turning several times, until golden and cooked through, about 7 minutes. Remove the mushroom from the pan and keep it on a warmed serving plate, gill side up, covered loosely with aluminum foil. Don’t wipe out the pan; just put it back on the stove.

If you’d like to heat the tomato, warm a teaspoon or so of butter or oil in the pan over medium-high heat. When hot, add the tomato slice and sear well on one side only. Sprinkle the top (raw) side with a little salt and pepper. Remove the tomato using a thin spatula and place it, seared side up, on the underside of the cooked mushroom and cover them. Don’t wipe out the pan; just put it back on the stove. Alternatively, just lay a beautiful slice of room-temperature raw tomato on top of the mushroom. Melt 2 teaspoons butter or heat more oil in the same skillet over medium heat. When hot, add the beaten egg and let it cook, undisturbed, just until it starts to set on the bottom. Reduce the heat to low and, using a heatproof rubber spatula, stir the egg, incorporating any bits of mushroom and tomato left in the pan. Add the chives and some salt and pepper, and cook, stirring continually, until it’s done to your liking. Spoon the scrambled egg over the tomato and garnish with a little more snipped chives. Serve right away.