Instant Pot Mississippi Roast with Pepperoncini and Butter

This Instant Pot Mississippi Pot Roast is an easy, flavorful dinner that yields tender, juicy beef in a savory, tangy sauce. A well-marbled chuck roast cooks until it falls apart in a buttery sauce flavored with ranch seasoning, au jus mix, pepperoncini, onions, and a splash of pepperoncini juice. Serve it over mashed potatoes or rice, pile it into sandwiches, or add vegetables to the Instant Pot for a complete one‑pot meal.

I’ve made this recipe for years and adjusted it over time based on what works best in my kitchen. I tested searing versus no searing, reduced the butter from older versions, tried substitutes for au jus when needed, and developed a faster “chunk” method that shortens pressure-cooking time while maximizing browned surface for extra flavor. If you enjoy hearty Instant Pot beef dinners, this version of Mississippi pot roast is a reliable favorite.

For quicker cooking, cut the chuck roast into 1½ to 2‑inch chunks. That method reduces the high‑pressure cook time to just 30 minutes and creates more surface area for browning, which adds flavor.

Why You’ll Love This Instant Pot Mississippi Pot Roast

• Great leftovers. The beef reheats well in its cooking liquid and tastes even better the next day.
• Weeknight friendly. The Instant Pot does the heavy lifting, and the chunk method makes it practical on busy evenings.
• Bold, balanced flavor. Ranch, au jus, pepperoncini, onion, and browned beef create a rich sauce with bright tang.
• Flexible cooking options. Make a whole roast for classic slices or cut into chunks for faster shreddable pieces.
• One‑pot dinners made easy. Add potatoes, carrots, and mushrooms after the beef cooks for a full meal.

What Is Mississippi Pot Roast?

Mississippi pot roast is a simple American-style pot roast built around chuck roast, ranch seasoning, au jus gravy mix, pepperoncini, and butter. It’s commonly made in a slow cooker, but the Instant Pot version gets you fall‑apart tender beef much faster. My Instant Pot method also uses diced onion and beef broth, and I recommend searing the beef first when time allows to deepen the flavor.

A Few Notes About the Ingredients

Here are a few tips to help you shop and prepare.

Chuck roast: A 3–4 pound well‑marbled chuck roast is ideal—flavorful, affordable, and forgiving. Boneless short ribs also work if you want a richer, more premium option.

Ranch seasoning: A 1 oz packet of ranch seasoning provides the classic tang and herb notes that define Mississippi pot roast.

Au jus or substitutes: Au jus gravy mix is traditional, but if you can’t find it, brown gravy mix or onion soup mix can be used with slightly different results.

Pepperoncini: Five or six whole pepperoncini are a good starting point; add more if you like extra tang. Reserve about 1/4 cup of the pepperoncini juice and add it to the sauce for bright acidity.

Butter: The recipe uses 4 tablespoons of unsalted butter. Many older versions used more, but chuck roast already contributes fat and richness, so 4 tablespoons is plenty.

Onion and broth: Diced yellow onion cooks down into the sauce for depth and helps thicken it naturally. Use beef broth to deglaze and flavor the pot.

Please scroll down to the recipe card for exact ingredient quantities and step‑by‑step instructions.

Should You Sear the Roast First?

Searing the beef before pressure cooking is optional but recommended. In side‑by‑side tests, seared beef developed deeper flavor, better texture, and improved tenderness. If you’re short on time, skip searing and the roast will still be tender, though with slightly less browned flavor.

Whole Roast or Chunks?

Both approaches work. Leave the chuck roast whole for a classic pot roast that yields larger shreddable pieces and adjust pressure time by roast weight. Cut the roast into 1½ to 2‑inch chunks to shorten the cooking time—chunks require about 30 minutes at High Pressure and brown more evenly when seared.

How to Make Mississippi Pot Roast in the Instant Pot

1. Prepare and sear the beef

Pat the chuck roast dry. Leave it whole or cut into 1½–2 inch chunks for the faster method. Season with ground pepper. Set the Instant Pot to Sauté, add oil, and sear the beef until nicely browned on all sides. Work in batches if using chunks to avoid overcrowding. Transfer browned beef to a plate.

2. Sauté the onion and deglaze

Sauté diced yellow onion until it softens. Pour in beef broth and scrape the bottom of the pot to loosen browned bits—this adds flavor and prevents burn notices when pressure cooking.

3. Add the remaining ingredients

Return the beef to the pot and add ranch seasoning packet, au jus mix (or substitute), pepperoncini, pepperoncini juice, and butter.

4. Pressure cook

Lock the lid and cook on High Pressure according to roast size:

• 3‑pound whole roast: 60 minutes
• 4‑pound whole roast: 70 minutes
• 5‑pound whole roast: 80 minutes
• 1½–2‑inch chunks: 30 minutes

5. Natural release and finish

Let the pressure release naturally—ideally 20–30 minutes. If short on time, allow at least 10–15 minutes of natural release before carefully finishing the release. The beef should pull apart easily; if not, pressure cook a bit longer.

How to Add Vegetables

To make a one‑pot meal, add vegetables after the beef’s initial pressure cook. Wait for at least 10–15 minutes of natural release, then open the lid and add baby potatoes, carrots cut into 1‑inch pieces, and mushrooms. Lock the lid and cook on High Pressure for 5 minutes, then allow a natural release. This keeps vegetables tender but not mushy.

Make the Sauce Thick or Thin

The cooking liquid will be fairly thin when you first open the pot. For sandwiches, a thinner sauce is ideal for dipping. For serving over mashed potatoes or rice, thicken the sauce: transfer beef and vegetables to a serving dish, set the Instant Pot to Sauté, whisk in a cornstarch slurry (1 tablespoon cornstarch + 1 tablespoon water), and simmer until it reaches your desired consistency. Skim excess fat before thickening if needed.

Slow Cooker and Oven Options

This recipe adapts well to a slow cooker: sear the roast, brown the onion, combine everything in a slow cooker, and cook on LOW for 8–10 hours. For the oven, use a covered Dutch oven at 325°F and braise for about 2–3 hours until tender, adding vegetables during the final portion of cooking.

Storage, Freezing, and Reheating

Store leftovers with some cooking liquid in an airtight container in the refrigerator for 3–4 days. The sauce firms when chilled, making it easy to skim fat. Freeze portions with a bit of cooking liquid to keep the beef moist; thaw in the refrigerator and reheat until the internal temperature reaches 165°F.

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This Instant Pot Mississippi Pot Roast is a dependable, flavorful meal that’s easy to scale and adapt. Serve it with mashed potatoes or rice, use leftovers for sandwiches, or add vegetables for a hearty one‑pot dinner.

RECIPE