Place farro in a mesh basket strainer and rinse under cold, running water for 1 - 2 minutes. Add farro to a medium pot with 3 cups of water and 1 teaspoon of kosher salt. Bring mixture to a boil over high heat, reduce heat to low and cook until al dente (soft on the outside, some bite left on the inside, about 25 - 30 minutes). If the farro has reached a desired texture, but hasn't absorbed all of the water, drain and return to the pot. Turn off heat and cover.

While the farro is cooking, warm extra virgin olive oil over medium heat in a large skillet. Once you see the oil start to shimmer, add sliced leeks. If you have difficulties recognizing the shimmer level of oil, try testing the heat level by dropping one slice of leek in the oil. If it doesn't sizzle, you need to warm the skillet more. If you hear a satisfying sizzle when the leek hits the oil, it is ready. If the oil is smoking in skillet, then it is too hot and you need to lower the heat (or start over). Cook leeks until they start to soften, stirring occasionally (5 - 7 minutes). Add garlic and cook until soft and fragrant, stirring occasionally (1 - 2 minutes).

Stir in white beans, chopped parsley and preserved lemon, then transfer the entire mixture to the pot with the cooked farro, stirring to combine. Season to taste with kosher salt and freshly ground black pepper.