Farro with Spring Vegetables

INGREDIENTS

• 3 Tbs. olive oil
• 1/2 yellow onion, finely chopped
• 2 celery stalks, finely chopped
• 1 oz. pancetta, finely chopped (optional)
• 1 1/2 cups farro, rinsed
• 1/2 cup dry white wine
• 4 cups chicken or vegetable stock
• 1/4 tsp. salt, plus more, to taste
• Freshly ground pepper, to taste
• 1 bunch asparagus, about 1 lb.
• 1 Tbs. unsalted butter
• 2 leeks, white and light green portions, rinsed well and cut into matchsticks
• 2 cups fresh or thawed frozen English peas
• Grated zest and juice of 1/2 lemon
• 2 Tbs. chopped fresh flat-leaf parsley
• 3-oz. piece Parmigiano-Reggiano cheese