Begin by heating a dry skillet over medium heat. Add your choice of almonds or pistachios and toast them for about 5–7 minutes, stirring frequently, until they are golden brown and fragrant. Once done, transfer the nuts to a plate to cool completely.

Next, take your oranges and grapefruit, peel away the skin and pith. Carefully segment the fruits by cutting between the membranes to release the juicy segments. Place the citrus segments in a bowl, setting aside some juice to use in the dressing later.

In a medium bowl or jar, combine high-quality olive oil with the reserved citrus juice, Dijon mustard, honey, and a pinch of salt and black pepper. Whisk or shake vigorously until emulsified and smooth.

In a large salad bowl, toss together the arugula, citrus segments, and red onion. Mix them gently to avoid bruising the greens.

Drizzle the vinaigrette over the arugula and citrus mixture. Toss gently to coat the greens without crushing the delicate leaves.

Crumble the goat cheese over the top of the salad, followed by the toasted nuts. Distribute these toppings evenly. Serve immediately.