Heat the oven to 120°C/235°F/gas mark 1. Place the rhubarb pieces in a medium, shallow baking dish and drizzle over the honey, add the orange juice, and scatter over the sugar and star anise.
Cover the dish loosely with a piece of greaseproof paper and place the rhubarb in the oven for 20–25 minutes, or until the rhubarb is soft but not broken down. Remove from the oven and set aside.
Meanwhile, season the venison all over with salt and pepper. Heat 1 tablespoon of the olive oil in a medium pan over a high heat. When it’s really hot, add the venison loin. Cook, turning regularly, for 4–5 minutes for medium–rare. Remove the meat from the pan and allow it to rest somewhere warm for 3–4 minutes.
Divide the rhubarb equally between four large plates, reserving the syrup in the bottom of the dish. Cut the loin into thick slices and lay it on and around the rhubarb. Scatter over the chard or other salad leaves, and drizzle over the reserved honey-and-anise syrup. Finish with a drizzle of the remaining olive oil and serve straight away.