Preheat your oven to 190°C / 170°C fan / 375°F (190°C) / gas mark 5.
Prepare the turnips: Slice off the tops and bottoms, then cut into quarters. Use a small sharp knife to peel the skin from each wedge.
Place the wedges in a roasting tray, drizzle with oil, season with salt, and toss with your hands to coat evenly.
Roast the turnips for about 30 minutes, turning occasionally. They are ready when they are soft, tender, and have developed a beautiful golden color.
While the turnips cook, prepare the apples. Halve them, remove the core, and cut each half into five wedges.
Place the apple wedges in a bowl, drizzle with a little oil, and season with salt and a generous sprinkle of sugar.
Make the glaze: In a wide frying pan, combine the cider, vinegar, and 50g (1.76 oz) of sugar.
Bring to a boil, then reduce to a simmer for 5 minutes until it thickens slightly.
Pour the glaze into a bowl and set aside.
About 5 minutes before the turnips are done, wipe out the frying pan and place it over a high heat.
Once very hot, add the apple wedges in a single layer. Flash-fry for a few seconds on each side until caramelized.
Turn off the heat and let them finish cooking in the residual heat of the pan.
To serve, transfer the roasted turnips to a serving bowl.
Add the caramelized apple wedges and drizzle generously with the cider glaze, tossing gently to combine.
When buying turnips, give them a squeeze. They should feel firm and rock-hard. Any softness can indicate a woody, unpleasant texture inside.
Don't be afraid to get your pan screaming hot for the apples. A quick, high-heat sear is key to getting that beautiful color without turning them to mush.
