Heat the oil in a large pot with an oven-proof lid over medium-high. Add the onion and sauté for 2 minutes. Turn the heat to medium and add the bacon. Sauté until the onion is translucent and the bacon is cooked (though it won’t be crispy).
Add the farro and lemon juice and turn the heat to high. Cook until the farro absorbs the juice. Add the chicken broth and bring to a boil. As soon as it boils, set the lid on the pot and put it into the oven.
Bake for 30 to 35 minutes until the farro is just tender, with no crunch. Remove from the oven and add the peas and asparagus. If the farro looks dry, add 1/4 cup of water or broth. Give it all a good stir and put it back into the oven for another 7 to 8 minutes until the vegetables are just tender (keeping in mind they will continue to cook a little once out of the oven).
Remove from the oven, add mint, salt, and Parmesan. Taste and add freshly ground black pepper along with more salt if needed. Serve immediately.
If using pearled farro (as opposed to semipearled), scale back the broth to 2 1/2 cups and add more as needed. Also, keep any eye on the clock, since pearled farro cooks more quickly than semipearled. If English peas are not in season, use frozen, defrosted peas.