Preheat oven to 450 degrees.
Heat 1 tsp olive oil in a large skillet over medium heat. Add garlic, mushrooms, and rosemary. Cook until mushrooms are golden and no liquid remains in the pan.
Turn heat to low and add greens. Cook until greens are wilted and bright green.
In a medium bowl, combine farro, greens/mushrooms, 1 cup gruyere, and salt and pepper.
Lightly oil a 9x9 baking dish. Evenly distribute farro mixture in baking dish.
In a bowl, combine panko, 1 tsp olive oil, and 1/2 cup gruyere. Top farro with panko mixture.
Bake for 15 minutes or until the panko is golden brown. Top with parsley and serve hot.