Preheat oven to 400°F and line a large baking sheet with parchment paper.
Bring a medium pot of water to a boil. Rinse the farro and add it to the boiling water. Reduce the heat and simmer, covered, for 25-30 minutes, or until tender but chewy. Drain and spread on a plate to cool and dry.
Spread the Brussels sprouts and red onion wedges onto the baking sheet and drizzle with olive oil, balsamic vinegar, maple syrup and generous pinches of salt and pepper. Toss to coat and roast until tender and browned around the edges, 30-40 minutes.
Meanwhile in a large bowl, combine 2 teaspoons of olive oil, lemon juice, Dijon mustard and pinches of salt and pepper. Add the farro and toss. Add the Brussels sprouts, pecans and cranberries. Toss and season to taste with more salt, pepper and lemon juice. Serve with microgreens to garnish.