Grease an 8-inch by 8-inch baking dish with a little bit of vegetable oil. Set aside.
Add Brussels sprouts and bacon to a Dutch oven.
16 small Brussels sprouts, cut into quarters, 4 slices regular-cut bacon, cut into ½-inch pieces
Transfer to the oven and roast, uncovered, for 30 minutes, stirring everything around halfway through. When you have about 10 minutes left, peel, core and cut the apple into 1-inch chunks.
1 large honeycrisp apple
Stir the apple chunks into the Brussels sprouts and bacon mix.
Transfer the mix back into the oven and continue to roast until the Brussels sprouts are completely tender and the bacon is almost fully cooked and crispy (about another 30 minutes). Stir everything around halfway through.
Transfer the mix to a bowl. Turn down the oven temperature to 325 degrees F.
Add the vegetable oil to the Dutch oven (you don't need to clean it first.) Heat the oil until shimmering, then add the bread cubes and the sage and fry just until the sage is starting to lose its bright green color (about 3 minutes).