Cut the loaf of bread into 1" cubes and leave out overnight so that they become slightly stale (this helps them from turning to mush when you add the liquid). This step can (and should!) be done at home.
Core and chop the apple and the fennel into bite sized pieces. Reserve the fennel fronds if they came attached. Dice the onion.
Heat the oil in a dutch oven over medium high heat. Add the onions, apple, fennel, sage, and salt. Saute until the onions and fennel have softened, 7-10 minutes.
Add the bread to the dutch oven. Pour the broth over the stuffing mixture, toss quickly to combine everything, and cover the dutch oven. Allow the stuffing to absorb the liquid over low heat for about 5 minutes. Uncover, toss, and serve!