In a skillet set over medium to high heat, add in the olive oil.
Add in the onion.
Cook for 5 minutes or until soft.
Add in the garlic and cook for an additional minute.
Add in the sliced cremini mushrooms.
Cook for 5 minutes or until soft.
Add in the powdered onion, chopped thyme, Worcestershire sauce, dash of black pepper and salt.
Cook for 1 to 2 additional minutes.
Remove from heat.
In a bowl of food processor, add in the farro, can of cannellini beans, half of the spinach and the onion mix.
Pulse on the highest setting until evenly mixed.
Shape the mix into 6 patties and place onto a baking sheet lined with a sheet of parchment paper.
Place into the fridge to chill for 1 hour.
In a separate skillet set over medium heat, add in ½ teaspoon of olive oil.
Add in the burger patties.
Cook for 3 to 5 minutes on both sides or until browned.
Transfer onto burger buns.
Top off with the remaining spinach.