Melt 1 tablespoon butter in a heavy-bottomed pot (I use my Le Creuset braiser) over medium heat.
Stir in 1 diced onion and 2 minced garlic cloves until softened, 3 to 4 minutes.Stir in 1 cup farro for about 1 minute, to toast the grains. Stir in 2 cups low-sodium chicken or beef or vegetable broth and bring to a boil over high heat. Once boiling, reduce to low and cook uncovered, stirring often, for 10 to 20 minutes, depending on the package instructions. Stir in 1/2 cup more broth at a time until the farro is tender and the mixture is very creamy, a risotto-like consistency.
Stir in 1/2 cup grated Parmesan cheese, 1 cup roughly chopped spinach, and the juice of 1 lemon. Taste and adjust salt and pepper as desired. I often don’t add salt at all if my chicken broth was really salty!
Remove from heat. It might continue to thicken, so just add another splash of broth to loosen to your desired consistency if it does. Garnish with more parmesan and any chopped fresh herb if you have some onhand!