Zest and juice half an orange. Remove peel and pith from remaining oranges and cut fruit into segments. Season pork medallions liberally with salt and pepper.

Heat 1 tablespoon oil in a large sauté pan over medium-high heat. Working in batches so you don’t crowd the pan, sear pork until golden brown and cooked to an internal temperature of 145° F, 3 to 6 minutes per side. Add more oil to the pan as needed. Remove cooked pork to a warm plate and cover with foil.

Reduce heat to medium and add garlic and shallots; cook until fragrant, 1 to 2 minutes. Deglaze pan with reserved orange juice and white wine, using a wooden spoon to scrape up any browned bits in the bottom of the pan. Reduce liquid to about 2 tablespoons.

Remove pan from the heat and swirl in butter, 1 tablespoon at a time. Stir in orange zest, orange segments, capers and tarragon. Warm over low heat, if necessary. Serve pan sauce over pork medallions.