Place bacon in a skillet over medium heat; cook and stir until crisp, about 10 minutes. Remove bacon from skillet, reserving 1 to 2 tablespoons bacon grease, to your preference.
Bring a large pot of water to a boil. Cook rutabagas in the boiling water until very tender, 15 to 20 minutes. Drain rutabagas and return to the pot.
Mix reserved bacon grease, butter, salt, and pepper into rutabagas; blend using an electric mixer until smooth. Stir chopped bacon into the rutabaga mixture.