Begin by seasoning your chuck roast generously with salt, ground black pepper and granulated garlic.
Cook your chuck roast according to the method that is most comfortable for you. I cooked mine in the Instant Pot. I added 4 cups of beef broth to my 8 qt Instant Pot and cooked on high pressure for 90 minutes. You may also cook on a stove top pressure cooker, in the oven or any other method that allows you to easily shred the beef once it’s done.
In a large baking dish, mix your mozzarella cheese, sharp cheddar cheese and room temperature cream cheese very well. Leave your cheese-filled baking dish aside for later.
Chop your onion and garlic cloves. Leave it aside to sautee later with the shredded beef.
Once your chuck roast is done cooking, transfer it to a plate and begin shredding the beef. You can use two forks to get the job done or I have found that a hand mixer gets it done fairly quickly. Set aside half cup of your beef broth for later.
Preheat your oven to 350 degrees.
In a medium skillet, heat up your oil and begin cooking your chopped onions. Allow the chopped onions to cook until translucent, then cook your minced garlic for about 10-15 seconds or until fragrant. You do not want to burn the garlic. Immediately add in your beef broth and shredded beef. Sautee until well incorporated and flavors are well combined. At this point, you may try your shredded beef for flavor. If it tastes good, great! If it needs a little umph, feel free to add more granulated garlic, salt, ground black pepper or any other spices you enjoy.
Once the beef broth has reduced and your shredded beef is super flavorful, remove the beef from your pan and combine it with all your cheeses in the baking dish you prepared during step 3. After your shredded beef and cheeses are well combined, top everything off with more mozzarella cheese.
Your oven should be preheated at 350 degrees by now, go ahead and place your baking dish uncovered inside your oven. Bake at 350 degrees for 30 minutes. Broil for the last few minutes. My oven is really fast so it only took 2-3 minutes but some ovens do take a bit longer to give you a desired broiled effect. Keep an eye on your dip after setting your oven to broil to ensure your cheese does not burn.
Chop up your green scallions to garnish the top of the dip. This step adds a little extra flavor and makes the dip look pretty but it is completely optional.
Your shredded beef and cheese dip is ready to be served! Enjoy this delicious appetizer hot with tortilla chips, toasted bread or even crackers!