Spray the bottom of the crockpot with nonstick cooking spray.: When you press your hand near the inner pot, you should feel a thin, even sheen that prevents sticking. This small step helps the saucy mixture release easily and keeps cleanup quick, which I always appreciate after a busy day. If you skip this, melted butter and juices can cling to the ceramic, making shredding and scraping harder later, so take a moment to coat the base evenly.
Add 2 pounds boneless skinless chicken breasts to the crockpot.: As you nestle each piece into the pot, notice the firm, pale texture of raw chicken , which will relax and become tender during cooking. Laying the breasts evenly ensures they all cook at the same rate and absorb the sauce uniformly. Avoid overcrowding, because packed pieces can lead to uneven cooking where the center stays less tender.
Pour in 1/2 cup pepperoncini juice from the jar and then add 10 pepperoncini peppers on/around the chicken.: The briny aroma should be bright and slightly vinegary as it hits the warm crockpot, which wakes up the other seasonings. Arrange the peppers around the chicken so each piece benefits from their tang. A common mistake is using too little brine, which can leave the sauce flat, so measure carefully to balance richness and acidity.
Sprinkle the chicken with 1 packet ranch seasoning powder and 1 packet au jus mix, then place the pieces of 1/2 cup unsalted butter on top.: As the powders dust the surface, you may notice a savory, herby scent that promises depth. Placing the butter on top allows it to melt slowly, basting the chicken and helping the seasonings dissolve into the sauce. If the butter is left in one big chunk, it can pool instead of integrating, so I slice it into pieces for even melting.
Cover and cook for 3-4 hours on high or 6-8 hours on low.: During the cook, the kitchen will fill with a warm, savory smell and occasional soft bubbling. The low and slow method yields a more developed sauce and ultra tender chicken , while the high setting speeds things up with slightly less depth. A typical error is lifting the lid too often to check, which lets heat escape and extends cook time, so resist peeking unless necessary.
Shred the chicken, then stir into the sauce. Serve over mashed potatoes and enjoy!: When you shred the cooked chicken , it should fall apart with gentle tugs and be silky from the sauce coating each strand. As you fold it back into the liquid, the meat absorbs more flavor and the sauce thickens slightly. If the meat seems dry, it likely cooked a bit too long or lacked enough liquid earlier, so reserve some cooking juices to moisten while shredding.