Preheat your oven to 400°F / 200°C.
Place the scrubbed beet in a small loaf pan and add enough water to come about a quarter of the way up its side.
Cover the pan tightly with aluminum foil and roast for about 1 hour, or until tender when pierced with a skewer.
While the beet roasts, cook the farro.
Combine the farro and 2½ cups / 600 ml (20.3 fl oz) of water in a heavy-bottomed saucepan over high heat.
Bring to a boil, stir once, then reduce the heat to a simmer.
Cover and cook for about 50 minutes, or until the farro is tender but still has a firm bite (al dente).
Drain any excess water and set aside.
Prepare the onions. On a baking sheet, toss the thinly sliced red onion with 1 tsp (5 ml) olive oil, salt, and pepper.
Spread into a single layer and roast for 15 to 20 minutes, stirring once, until softened and beautifully caramelized.
Once the beet is cooked and cool enough to handle, the skin should slip off easily. Use a paring knife to help if needed.
Chop the beet into bite-sized pieces.
Make the vinaigrette.
In a small bowl, whisk together the fresh grapefruit juice, aged sherry vinegar, 1 Tbsp (15 ml) extra virgin olive oil, and a pinch of salt and pepper until well combined.
Assemble your salad.
In a large bowl, combine the cooked farro, chopped beet, half of the caramelized onions, fresh watercress, and grapefruit segments.
Pour the vinaigrette over the salad and toss gently to combine.
Divide among plates and top with the remaining caramelized onions.
Serve immediately and enjoy!
