Place roast on a tray and season with salt and pepper on both sides. Sprinkle the flour over the roast and massage it into the meat.
Heat oil in a large skillet over medium high heat. Once it is hot, place the roast and pan sear for 5-6 minutes or until browns. Turn it over and sear on the other side. Transfer to the slow cooker.
Add the butter and pepperoncini. Cover and set "LOW" for 9-10 hours.
While the roast heats, mix together mayonnaise, sour cream, ranch mix, dill and lemon juice. Whisk until well combined.
Pour the mixture over the roast, cover and continue cooking until fork tender.
After 9-10 hours, test to adjust the seasoning to your liking.
Shred the meat and mix with the gravy together.
Garnish with chopped parsley and serve with bread or over mashed potatoes. Enjoy!