Preheat the oven to 400°F (200°C). Trim the beet greens leaving about 1/2 inch of stem (reserve greens for another use). Wash beets thoroughly to remove dirt, then pat dry.

Roast beets whole

Rub the beets with 2 tbs olive oil and sprinkle with 1 tsp kosher salt and 1/2 tsp black pepper. Wrap each beet loosely in aluminum foil (or place in a covered baking dish). Roast on a rimmed baking sheet for 45–60 minutes, depending on size, until a paring knife slides easily into the center.

Cool and peel

Remove beets from the oven and let cool 10–15 minutes until they are safe to handle. Unwrap and gently rub the skins off with your fingers or a paper towel (skins should slip off). Slice beets into 1/4-inch rounds or wedges, depending on preference. Set aside to cool slightly.

Walnuts

If walnuts are not already roasted, preheat a small skillet over medium heat. Add 1/2 cup walnuts and toast, stirring frequently, 4–6 minutes until fragrant and slightly darker. Remove to a plate to cool, then roughly chop. (If using store-roasted walnuts, you can roughly chop without toasting.)

Lemon Dressing

In a small bowl or jar combine 3 tbs fresh lemon juice, 3 tbs extra-virgin olive oil, 1 tsp Dijon mustard, 1 tsp honey, 1 tbs finely minced shallot, 1/2 tsp salt, and 1/4 tsp freshly ground black pepper. Whisk or shake vigorously until the dressing emulsifies and is slightly thickened. Taste and adjust seasoning—add more honey if too bright or more lemon if you prefer more acidity.

Assemble Salad

In a large bowl, place 4 cups baby arugula. Add the sliced apple and gently toss with about half of the dressing to lightly coat the greens and fruit.

Arrange the warm or room-temperature roasted beet slices on top of the dressed arugula and apple. Sprinkle the crumbled goat cheese evenly over the salad.

Scatter the roasted, chopped walnuts over the salad. Drizzle additional dressing to taste (reserve any extra dressing in the refrigerator for up to 3 days).

Finish with a small pinch of flaky sea salt or additional freshly ground black pepper if desired. Serve immediately while beets are slightly warm or at room temperature.