To a medium saucepan, add the farro, thyme bundle, bay leaf, 2 1/2 cups of the chicken stock and salt to taste. Cover and bring to a boil, then reduce to a simmer and cook until the farro is tender, adding 1/2 cup water if the pot looks dry towards the end of the cooking time, 25 to 30 minutes. Discard the thyme bundle and bay leaf and strain out the farro.
Add 2 tablespoons of the olive oil to the pan that the farro was cooked in and return to heat. Add the fennel and half of the diced onion and saute until translucent, 5 to 7 minutes. Add the cannellini beans and garlic and cook for 2 minutes. Add the cooked farro and grated Parmesan cheese and stir to combine. Fold in the chopped fennel fronds.
Preheat the oven to 400 degrees F.
Season the pork tenderloin generously with salt and 1 tablespoon of the fennel pollen. Heat 2 tablespoons olive oil in a large saute pan over medium-high heat. Add the pork and sear on all sides until evenly golden brown,10 minutes. Remove the pork from the pan and place onto a sheet tray. Reserve the pan that the pork was cooked in for later, draining off any excess oil. Transfer the pork into the oven and bake for 7 to 8 minutes, or until it reaches an internal temperature of 140 degrees F. Set aside to rest for 10 minutes, then cut the pork into 1/2-inch slices.
Place the saute pan that the pork was cooked in back onto the heat and add the remaining 2 tablespoons olive oil and the other half of the onion. Season with salt and crushed red pepper. Cook, stirring occasionally, until the onion is soft, 5 minutes. Add the peaches, whole-grain mustard, maple syrup, balsamic vinegar, remaining 1 1/2 cups chicken stock and remaining 1/4 teaspoon fennel pollen. Stir to combine and cook until reduced, 5 to 7 minutes. Season to taste with salt. Plate the farro, followed by the sliced pork tenderloin and a generous scoop of sauce. Garnish with whole fennel fronds.