Pork Tenderloin Medallions with Braised Fennel

From the garden

• 2 large fennel bulbs, trimmed, cored, cut into 1/2-inch wedges; a handful of fronds saved and chopped · about 2 pounds with stalks
• 4 cloves garlic, smashed
• 4 sprigs fresh thyme

From the pantry

• 1½ lb pork tenderloin, silverskin trimmed, sliced into 1-inch medallions · usually two tenderloins
• ¾ cup dry white wine
• ¾ cup chicken stock
• 3 tbsp olive oil
• 1 lemon, zest grated, then juiced
• 1 tsp Dijon mustard
• salt · to taste
• black pepper

1. Heat 2 tablespoons of the oil in a large, lidded skillet over medium-high. Lay the fennel wedges in a single layer, cut side down, and let them brown without moving for 4–5 minutes; work in two batches if they crowd. Season with salt and pepper.
2. Add the garlic and thyme, pour in the wine, and let it bubble 1 minute. Add the stock, cover, turn the heat to medium-low, and simmer 15–18 minutes, until a knife slides through the fennel with no resistance. Uncover and let the liquid reduce a few minutes to a glossy, spoonable sauce. Slide the fennel to a warm platter and keep the pan.
3. While the fennel braises, press the medallions with your palm to an even 3/4 inch and season well with salt and pepper. Wipe the skillet if it is very wet, add the remaining tablespoon of oil, and sear the medallions over medium-high 2–3 minutes per side, until browned and 140–145°F in the center. Do not overcook; tenderloin dries out fast. Rest 5 minutes on a board.
4. Return the fennel and its juices to the pan, stir in the mustard, lemon zest, and lemon juice, and taste for salt and brightness.
5. Arrange the medallions over the fennel, spoon the pan sauce over, and scatter the chopped fronds on top. Serve with boiled small potatoes or a bowl of rice.