This citrus salad is one of our favorite side dishes! To make it ahead of time, segment the citrus, slice and roast the fennel, and whisk together the dressing up to a day in advance. Assemble it when you're ready to eat!
Make the dressing: In a small bowl, whisk together the olive oil, lemon juice, garlic, and Dijon mustard.
In a medium bowl, toss the sliced fennel with a few drizzles of the dressing. Set aside for 15 minutes so the fennel softens a bit.
Assemble the salad on a platter by arranging half of the sliced fennel, all the roasted fennel, radicchio, and half of the citrus segments. Drizzle with a few spoonfuls of the dressing and sprinkle with salt. Layer the remaining fennel and the remaining citrus onto the salad. Top with the avocado, pine nuts, pecorino, and mint. Drizzle with more dressing, sprinkle with salt and pepper, and serve.