2 ½ fennel bulbs, cut in half lengthwise, core removed, sliced
½ radicchio head
Fresh mint leaves – 1 ½ tbsps
In a small bowl, whisk lemon juice with mustard. Add oil in a thin streak, whisking constantly. Add a sprinkle of salt and a couple sprinkles of pepper.
Add fennel slices into a large bowl. Top with the dressing, toss until coated. Sprinkle with salt and pepper. Note: this step can be done up to a day ahead; only you will need to cover the ready fennel with plastic wrap and chill.
Remove peel, white pith and seeds from grapefruits. Cut clean grapefruit wedges into smaller pieces. Add chopped grapefruit to fennel, mix to combine. Top with the dressing and mix again.
Arrange radicchio leaves on a large platter. Transfer salad from the mixing bowl on top of the leaves, sprinkle with chopped mint and serve.