From Food52.com; this salad would also come together great if both veggies were grilled and then cut into small pieces. Also, this basic dressing is my go-to for so many salads.

Core and slice the fennel as thinly as possible - if you have a mandoline, use it for this. Core and half the radicchio; slice into tagliatelle sized ribbons. Cut the proscuitto the same size as the radicchio. Mix vinegar, mustard, sugar, shallot or scallion, and salt & pepper together. Slowly whisk in olive oil or put all ingredients in a container with a tight fitting lid and shake to emulsify. Shave Parmigiano-Reggiano with a vegetable peeler and combine with radicchio, fennel, and proscuitto. Mix salad with enough of the vinaigrette to adequately dress. Let sit in refrigerator for 30 minutes, then serve.