Preheat oven to 400 degrees with a rack in the upper and lower thirds.

In a medium saucepan, combine farro and 1 teaspoon salt; cover with water by 2 inches. Bring to a boil and cook until tender, about 20-25 minutes. Drain, and transfer to a bowl.

Meanwhile, combine grapes, 1 tablespoon olive oil, sprinkle of salt and pepper on a baking sheet. Place onion slices on a separate baking sheet and drizzle with 1 tablespoon olive oil. Flip slices and drizzle with another tablespoon olive oil. Season with salt and pepper. Put the onions on the bottom rack of oven and the grapes on the top rack.

Roast grapes for about 35-40 min, until they burst and release some juice. Shake the tray once or twice during roasting. Roast onions for 30 minutes, then flip and add thyme sprigs. Roast another 20-30 minutes until soft and golden brown.

When cool enough to handle, remove thyme sprigs and give the onions a rough chop. Transfer roasted grapes and onions to bowl with farro. Toss with remaining 2 tablespoons olive oil and red wine vinegar. Toss well to combine and let cool, about 20 minutes.

Immediately before serving, gently toss in greens, almonds and scallions. Season with additional salt, pepper, and red wine vinegar if needed. Transfer to a platter, top with goat or feta cheese, if using.