In a medium bowl, mix together the farro and 4 cups of water. Soak for 30 minutes and drain well.
Heat the broth in a small saucepan and keep warm over low heat.
In a large saucepan or Dutch oven, heat the oil and butter over medium heat. Add the shallots and season with 1/4 teaspoon salt and 1/4 teaspoon pepper. Cook until softened, about 2 minutes. Add the drained farro and cook, stirring constantly until toasted, about 3 minutes. Add the wine and stir constantly until evaporated, about 2 minutes. Add 1/2 cup of the hot broth and stir constantly until completely absorbed. Continue adding the remaining broth, 1/2 cup at a time, until the farro is creamy and cooked through, about 30 minutes. Turn off the heat and stir in the currants, pine nuts, feta cheese, and the remaining salt and pepper. Transfer to a bowl and serve.
Cook's Note: To toast the pine nuts, arrange in a single layer on a baking sheet. Bake in a preheated 350 degrees F oven until lightly toasted, about 6 to 8 minutes. Cool completely before using.