- Rinse the fennel, then remove and reserve the fronds. Slice the bulb in half lengthwise (north pole to south pole). Using a sharp knife, carve around the core, removing and discarding it. Shave the fennel bulb on a mandoline.
- Mix buttermilk and salt in a medium bowl until the salt dissolves. Toss fennel in buttermilk, cover, and refrigerate. The buttermilk marinade will be very salty, which helps to draw water out of the fennel, and it’s the only component in the salad that is seasoned.
- Cut the oranges into supremes (retaining the flesh of the orange but removing the membrane of each wedge). Combine the juice and segments in a bowl and reserve.
- Separate the whites from the green stems of the scallions. Trim and discard the roots. Slice the whites into thin rings and put in small bowl. Thinly slice the greens on the diagonal and put in another small bowl.
- Shave the garlic and jalapeno on the mandoline. Gently toss the scallion whites, garlic, and jalapeño with the satsumas and juice to combine.
- Pick the fennel fronds from the stems and toss with the scallion greens and a few drops of olive oil. Pluck the shaved fennel from the buttermilk and drain on a paper towel, patting off the buttermilk.
- For each plate, place a 4-inch ring mold in the center of the plate. Pack the mold with one quarter of the fennel, pressing with the back of a spoon to compact. Layer one quarter of the orange mixture on top of the fennel, gently shaping it into the ring mold. Carefully lift the mold straight up to remove it from the plate. Sprinkle with the fennel frond mixture and croutons.
* You can make your own croutons by taking day-old Italian or sourdough bread, slicing it, then cubing it. Heat the cubes in olive oil over medium-high heat in a sauté pan for a few minutes until brown. Remove to a paper towel and sprinkle with salt. Homemade croutons have a short shelf life, so use right away.