Step 1

Preheat oven to 425°. Combine beets, oil, vinegar, several pinches of salt, and ¼ cup water in a baking dish. Cover tightly with foil and bake until beets are tender, 50–60 minutes. Uncover and let sit until cool enough to handle. Peel and cut each beet into 4 wedges, or 6 wedges if they are larger.Do ahead: Beets can be roasted 2 days ahead. Let cool; cover and chill.

Step 2

Toast coriander seeds, fennel seeds, and cumin seeds in a dry small skillet over medium heat, tossing occasionally, until slightly darkened and fragrant, about 3 minutes. Transfer to a spice mill, mortar and pestle, or small food processor; let cool. Pulse until coarsely chopped. Add cashews, pistachios, benne seeds, and ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt; pulse again until coarsely chopped.

Step 3

Toss roasted beets, red onion, oil, lime juice, half of sage, and ¼ cup dukkah in a medium bowl to combine; taste and season with salt. Arrange on a platter and top with more dukkah and remaining sage.Do Ahead: Dukkah can be made 1 week ahead. Store airtight at room temperature.