Transfer onion mixture to a large bowl. Add bacon to bowl, season with salt and pepper. Add biscuits and 3 cups of the chicken stock, stirring to combine. If the mixture looks too dry, add the last cup of chicken stock. Otherwise, leave it out.
Transfer dressing to a baking dish. Cover with foil or lid, bake for 30 minutes. Remove foil or lid and bake for another 20 minutes, or until the dressing is lightly browned. Enjoy!