Step 1

Place the chuck roast, au jus gravy mix, and ranch dressing mix into a slow cooker, making sure the chuck roast is coated in the gravy mix and dressing mix.

Step 2

Place the stick of butter on top of the chuck roast and place the pepperoncini peppers around the roast.

Step 3

Pour the water over everything.

Step 4

Cover the slow cooker and cook on low until the meat is fall-apart tender, about 8 hours.

Step 5

Transfer the meat and peppers to a cutting board and use two forks to shred the meat. Discard any fat.

Step 6

Strain the cooking liquid into a gravy separator or glass measuring cup.

Step 7

Skim the fat off the top and discard it.

Step 8

Pour the meat liquid into a small saucepan and cook it over medium-high heat on the stove-top.

Step 9

Slowly add the flour to the meat liquid as it cooks, whisking after each addition.

Step 10

Simmer the resulting gravy until it thickens, about 5 minutes.

Step 11

Return the meat and peppers to the slow cooker and pour the gravy over it.

Step 12

Serve hot over mashed potatoes.