Champagne chicken with mushroom pan sauce

Season both sides of the chicken breasts generously with kosher salt.

Brown over high heat in olive oil, in a pan wide enough for one layer and a couple of inches deep, about three or four minutes; season the top with black pepper and a few shakes of cayenne.

Turn and brown the other side a few minutes; turn off the heat and remove the chicken, not yet cooked through, to a plate.

Add butter to the pan over medium-high heat; once nearly melted add the sliced mushrooms and a big pinch of salt, letting their moisture deglaze the drippings, and brown them well.

Add the diced shallots and minced garlic and cook three or four minutes, until the shallots just turn translucent.

Sprinkle over the flour and stir for about a minute to take off the raw edge, until it starts sticking to the pan.

Pour in the sparkling wine, scraping the bottom with a spatula, and cook on medium-high a few minutes until reduced by about half and thick enough that a line dragged through it takes half a second to fill.

Add the tomato paste, thyme leaves and chicken broth; bring back to a simmer and add a generous splash of heavy cream.

Cook on medium-high about 10 minutes, until reduced and thick enough to coat a spoon.

Reduce the heat to low and stir in the aged balsamic vinegar.

Return the chicken and its juices; simmer between low and medium-low, a couple of minutes per side, flipping back and forth and basting the tops.

Cook until it reaches an internal 150, held at least 3 or 4 minutes; size and initial browning decide the time.

Taste the sauce for seasoning, take off the heat, spoon sauce and mushrooms over the chicken, and finish with more thyme leaves.

Serve on or beside mashed potatoes.