11/2 lb [680 g] red baby beets,
1 to 2 in [2.5 to 5 cm] in diameter
4 Tbsp [60 ml] extra-virgin olive oil
2 Tbsp water
Freshly ground black pepper
1 Tbsp plus 1 tsp sherry vinegar
1 Tbsp fresh orange juice, plus 2 oranges
2 Tbsp hazelnuts
1 ripe avocado, cut in 1/4-in- [6-mm-] thick slices
Flaky sea salt
Best-quality olive oil for drizzling
Preheat the oven to 400°F [200°C].
In a roasting pan, toss the beets with 2 Tbsp of the extra-virgin olive oil and the water and season with kosher salt and pepper. Roast until the beets look caramelized and feel tender when pierced with the tip of a knife, about 25 minutes. When cool enough to handle, slip the skins off the beets and cut into quarters.
In a medium bowl, toss the beets with the remaining 2 Tbsp olive oil, the sherry vinegar, and orange juice. Season with kosher salt and pepper and let stand until the beets have absorbed the flavors of the dressing, about 30 minutes.
In a small, dry frying pan over medium heat, toast the hazelnuts until fragrant, 3 to 5 minutes. Lay out on a work surface and let cool. With the bottom of a heavy pan, crush the nuts.
Section one of the oranges by cutting off both ends. Set it on one end, and use a paring knife to cut away the peel and pith in strips, starting at the top and following the curves to the bottom. Then, holding the orange in one hand, carefully insert the blade of the knife between the flesh and the membrane to cut out the sections without any membrane attached. The sections should come out easily. Repeat with the remaining orange, and set aside.
Arrange the beets on a serving platter with the avocado slices, and sprinkle them with sea salt and pepper. Distribute the orange sections throughout the salad and sprinkle with the crushed toasted hazelnuts. Finish with a drizzle of best-quality olive oil. Serve immediately