Place chuck roast in the bottom of your slow cooker. You can brown it first, but I generally skip that step with the slow cooker version since it doesn't seem to make a perceptible flavor difference.
Add a cup of beef broth, a handful of whole peeled garlic cloves (or to taste -- I add a bunch because we all like garlic here and they're so good as a sandwich topping at the end), and the entire jar of pepperoncini, including liquid.
Cook on low for 8-10 hours.
Remove beef and shred, reserving garlic, peppers, and juice for topping sandwiches.
Serve on French rolls with provolone or mozzarella cheese. You can also enjoy your Italian beef in a bowl or on a low carb wrap, if you're low carb, or on a gluten free bun, if you're gluten free.
You can also make this with mild pepper rings, if you prefer. Plus, you may even have leftovers for tomorrow: Italian beef makes great quesadillas.
Four Ingredient Slow Cooker Italian Beef from Mashup Mom: https://www.mashupmom.com/four-ingredient-slow-cooker-italian-beef/