Preheat oven to 400 degrees. The farro will cook faster if you soak it in a bowl, covered with hot water for an hour. After soaking, drain farro and rinse in a colander. Heat a saucepan over medium heat. Add 1 tablespoon of olive oil to the pan, and then the farro. Stir to coat; then toast farro for 2 minutes until it smells nutty. Add two cups of water, bring to a simmer, cover and cook for 45 minutes, or until tender, stirringly occasionally. If the water hasn’t fully absorbed, strain.
Slice the carrot in half lengthwise and then into diagonal slices, ½” thick. Toss with one tablespoon of olive oil, sea salt and pepper and roast in oven for twenty minutes, or until tender. In a cast iron pan or toaster oven, toast the nuts for about five minutes, until golden brown.
In a food processor, combine the carrot leaves, the 6 tablespoons of olive oil, garlic and some sea salt and process until finely minced. Add the toasted nuts and pulse until finely chopped. Add Parmesan, if using, and pulse enough to combine. Taste and season to your liking.
Combine the cooked farro, ¼ cup of pesto, roasted carrots and juice from the lemon. Garnish with sliced scallion.