Combine the apple and celery into a bowl. Add in the vinegar, mustard, olive oil, salt, and pepper. Mix well to combine. Set aside.
To make the bbq sauce
Add the oil to a saucepan over medium heat. Add in the diced shallots. Cook til softened about 5 minutes. Then add in the garlic and cook for 30 seconds.
Add in the cranberry sauce, ketchup, vinegar, mustard, Worcestershire sauce, salt, and pepper.
Bring to just a boil, then reduce to a simmer. Cook until the sauce thickens about 5 minutes.
If you want the sauce to be smooth, run it through a food processor or blender. Or you could allow it to cool enough to smooth it out with a sticker blender.
Assembly the sliders
Put the turkey on the sliders cold or heat it up first. Then add ¼ cup of turkey to each bun, roll, or biscuit.
Add 2 tablespoons of the slow and then top with the BBQ sauce.