You can use store-bought, pre-cooked beets, or make your own. You can roast the beets ahead of time and keep them stored in the fridge once they’re cooled.
Preheat the oven to 425°F. Wash the beets and pat them dry. Do not peel.
Place each beet onto a small sheet of foil; cut larger beets in half. Drizzle a bit of olive oil over the top and season lightly with sea salt. Wrap the beets tightly in the foil and place into a small baking dish.
Roast the beets at 425°F until they’re fork-tender– for about 30 to 45 minutes, depending on the size of the beets. Remove them from the oven, out of the foil, and cool them to room temperature.
Preparing Salad Ingredients:
Once the beets are cooled enough to handle, use a pairing knife to remove the peel, then slice the beets into thin wedges.
Prepare the citrus next: use a sharp knife to cut way the peel, then slice the oranges into thin wedges. Place into a bowl and set aside.
Next, prepare the fennel. Cut off the green stalks (the top part) and set aside for later. Set your mandoline slicer to the thinnest setting and thinly slice the fennel. Place it into a bowl and cover it with plastic wrap to keep the fennel from browning.
Finely chop the pistachios.
Making Salad Dressing:
For the salad dressing, start with the lemon zest. Add the zest of 1 large lemon into a large measuring cup. Squeeze out the lemon juice, straining out any seeds.
Pour in the olive oil. Use a zester to grate the garlic cloves and add to the dressing.
Add the two mustards, honey, and season with salt, freshly ground black pepper, and fresh thyme.
Whisk everything together and use the dressing when ready to serve. Cover and store the dressing in the refrigerator for up to 1 week.
Making the Salad:
Arrange the salad on a large platter or in a large salad bowl. Toss together the arugula with the thinly shaved fennel. Add the sliced beets over the bed of arugula.
Remove the burrata cheese from its container, then gently pull it apart with your hands into small chunks and arrange it evenly over the salad.
Add the citrus segments next, then sprinkle the diced pistachios over the top.
To garnish the salad, add small sprigs of fennel greens over the top.
Give the salad dressing one more whisk, then pour it over the top of the salad. Use two large spoons to toss the salad and enjoy! If not serving right away, keep the dressing on the side and keep the salad covered and refrigerated.