1. For best results, toast the walnuts in a 180°c/160°c (fan) for 5-7 mins. Don’t want to heat an entire oven just to toast some nuts? Add them to a dry frying pan over a medium heat and toss frequently for 3-5 mins. It’s important to keep them moving so they don’t burn.
2. Cut off the root of the radicchio and separate the leaves, cutting any large ones in half lengthwise. Add to a large mixing bowl.
3. Zest one of the blood oranges and set aside. To segment your oranges, cut a small slice from the top and bottom. Stand them up and carefully follow the contour of the fruit to remove the skin and white pith.
Over a small bowl to catch the juices, use a sharp knife to cut between the membranes of each segment. Set the segments aside, and squeeze all the juice from the remaining centrepiece of the fruit into the bowl.
4. Cut off an inch or so from the top of the fennel (reserving the fronds for later), and a small amount of the root. Remove the outermost layer. Now cut in half lengthwise.
Use a mandolin to finely slice the fennel, placing the now-exposed middle face down. No mandolin? No problem. Just slice as finely as possible using a sharp knife. For this, place the flat side down on your board (for stability) and carefully slice lengthwise again.
5. Add the sliced fennel to the same bowl as the radicchio, along with the blood orange segments, olive oil, balsamic vinegar, the orange zest, and about ½ of the reserved blood orange juice and fennel fronds. Season generously with sea salt, black pepper, and oregano. Mix well and check the seasoning.
6. Finally, split the ricotta between two bowls and season with salt and pepper. Build the dressed salad around the ricotta as artfully or rustically as you desire. Break over the toasted walnuts before finishing with a final drizzle of extra-virgin olive oil.