6 mandarin oranges, peeled and sliced crosswise into ¼-inch rounds
½ fennel bulb, thinly sliced (reserve fronds for garnish)
2 avocados, peeled, pitted, and sliced
1 small shallot, peeled and thinly sliced
¼ cup extra-virgin olive oil
2 tablespoons champagne vinegar
Salt and fresh ground black pepper
Divide orange slices between 4 salad plates. Layer with fennel, avocado, and shallot slices. Whisk olive oil and vinegar until emulsified. Season with salt and pepper. Drizzle dressing over the salad and top with fennel fronds. Serve immediately.