This is a clean version of the classic Slow Cooker Mississippi Roast recipe with no packets, no processed ingredients, no MSG. It takes just 20 minutes to assemble in the slow cooker and then cooks all day for a savory, delicious meal that will quickly become a family favorite.
Heat a skillet with oil over medium-high heat. While skillet is heating, season meat on both sides with salt and black pepper.
Add beef to heated skillet and sear on both sides until deep golden brown and lightly crusted, about 5 minutes per side.
Transfer meat to the bowl of a slow cooker (leave the skillet over heat). Add butter and stir until butter is melted. Add onions to butter and cook about 4 minutes.
Add flour and stir until no dry spots of flour remain, about 1 minute.
Scrape onions into the bowl of the slow cooker. Add sliced pepperoncini and the ingredients for the Ranch Herb Blend.
Cover and cook on low for 10 to 12 hours, until roast can be easily shredded with a fork.