Preheat the oven to 425 degrees. Toss the diced purple and sweet potatoes with 2 tbsp olive oil, salt, and pepper. Spread onto a baking sheet and roast, tossing periodically, until they are cooked through and begin to brown. Remove from the oven and set aside.
Fill a medium pot about half full with water and bring it to a boil. Add the rinsed farro, return to a boil, then reduce the heart to medium. Allow the farro and cook until tender and chewy, about 30 minutes. Drain any excess water.
In a pan, melt, 1 tbsp of butter over medium heat. Add the pecans, tossing them in the butter and toasting for about 5-7 minutes, until they are lightly browned. Remove the nuts from the pan and roughly chop.
Chop the parsley and dill, and chiffonade the mint.
In a bowl, mix together juice from half of the lemon, or more if you prefer, 3 tbsps olive oil, Dijon mustard, and salt and pepper.
In a large bowl, add the cooked farro, roasted potatoes, herbs, and pecans. Pour the lemon dressing over the top and mix well. Top with crumbled goat cheese, lemon zest, and a sprinkle of flaky salt and cracked pepper.
