Assemble all of your ingredients ('mise en place' as chefs say) because you'll be working very quickly.
Bring chicken broth to a boil and add farro. Simmer on low for 10 minutes and drain excess broth.
While farro is cooking, heat 1 T of olive oil in a large saute pan over medium heat. Once it's shimmering, add chopped onion. Season with salt and pepper. Saute onion until translucent and lightly browned about 5 minutes. Remove the onion from the pan and set aside.
If everyone in your house likes all the remaining vegetables, heat 1 more tablespoon of olive oil in the same pan. Once it's heated per above, add the peas and asparagus. Season with salt and pepper. Saute for about 3 minutes until both are bright green. You want the peas al dente.
If needed, add another tablespoon of olive oil along with the reserved onions, spinach, and garlic. Season with salt and pepper. Saute very quickly for about 30 seconds. You don't want the garlic to burn and the spinach will break down very quickly.
Squeeze the lemon juice over top of the vegetables and cook for a few seconds. Turn off the heat. Taste for seasoning.