Crockpot Pepper Steak with Peppers and Onions

Sweet peppers, tender beef, and a glossy brown sauce are what make Crockpot Pepper Steak with Peppers and Onions worth keeping in the regular dinner rotation. The beef turns spoon-tender…

By Brad
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August 6, 2026
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Reading time: 9 min

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Sweet peppers, tender beef, and a glossy brown sauce are what make Crockpot Pepper Steak with Peppers and Onions worth keeping in the regular dinner rotation. The beef turns spoon-tender without falling apart into shreds, and the peppers hold onto enough structure that every bite still has a little crunch and brightness. It eats like the kind of takeout-style dinner that usually takes more effort than it should, but the slow cooker does most of the work here.

The trick is giving the beef a quick toss in cornstarch before it goes into the crockpot. That thin coating helps the sauce thicken later and keeps the meat from tasting flat. Searing first matters too, even though it feels skippable on a busy day. Those browned edges add depth that the slow cooker alone won’t build. The sauce leans on beef broth, soy sauce, Worcestershire, and a little brown sugar, which gives you savory balance instead of a one-note salty gravy.

Below you’ll find the exact cooking rhythm that keeps the peppers from going mushy, plus a few smart swaps if you need to work with a different cut of beef or want to adjust the heat.

The Browned Beef Step That Keeps Pepper Steak from Tasting Flat

The biggest mistake in slow cooker pepper steak is treating the crockpot like it can create all the flavor on its own. It can’t. If the beef goes in raw, the dish still works, but the sauce tastes thinner and the meat ends up more one-dimensional. A fast sear gives you browned edges that deepen the whole pot, and the cornstarch coating helps those juices cling to the sauce instead of disappearing into the broth.

The second thing that matters is when the peppers go in. They need enough time to soften and take on the sauce, but not so much time that they lose all shape. In this version, they cook from the start, which gives you a softer, stew-like result. If you want brighter peppers, stir them in during the last hour on Low or the last 30 minutes on High.

What Each Ingredient Is Actually Doing in This Dish

• Beef sirloin or flank steak — Sirloin stays a little more tender after a long cook, while flank steak brings a beefier bite if it’s sliced thin across the grain. Either cut works, but thick slices won’t soften as evenly, so thin slicing matters more than the exact cut.
• Cornstarch — The first coating helps the beef brown and gives the sauce something to cling to. The second addition at the end thickens the cooking liquid into a glossy gravy, and that slurry needs cold water so it doesn’t clump.
• Bell peppers and onion — This is where the dish gets its sweetness and texture. Yellow onion melts down and seasons the sauce, while the peppers contribute color and a little bite. Red and green together give the best balance, but any mix of bell peppers works.
• Beef broth, soy sauce, and Worcestershire — These three build the savory base. Use low-sodium broth and soy sauce if you can, because the sauce reduces and concentrates during cooking. Worcestershire adds the deeper, rounder note that keeps the dish from tasting salty and thin.
• Brown sugar — Just enough to soften the edges of the soy and Worcestershire without making the sauce sweet. If you skip it, the sauce tastes harsher.
• Black pepper and smoked paprika — Pepper steak needs actual pepper flavor, not just the name. Smoked paprika adds a little warmth and depth, especially if your beef cut is lean.

How to Build the Slow Cooker Sauce So It Stays Rich, Not Watery

Coating and Searing the Beef

Toss the sliced beef with cornstarch until it looks lightly dusty, not paste-like. Then sear it in a hot skillet just long enough to pick up color on the edges. If the pan is crowded, the beef will steam instead of brown, and you lose the flavor boost that makes the sauce taste like it simmered all day.

Layering the Crockpot

Put the beef in first, then pile the onions, peppers, and garlic over the top. Whisk the liquid ingredients together before pouring them in so the seasoning is evenly distributed. A little extra broth can thin the sauce too much, so stick close to the measured amount unless you want more gravy for serving over rice.

Cooking Until the Beef Gives Easily

Cook on Low for 6 to 7 hours or High for 3 to 4 hours, until the beef breaks apart with a fork but still holds its shape. If it goes much longer than that, flank steak can turn stringy and the peppers can lose all texture. The dish is ready when the beef is tender and the sauce has a deeper color from the cooking juices.

Finishing with the Slurry

Stir the cornstarch and cold water together until smooth, then add it during the last 20 minutes. That’s the part most people rush. If you add the slurry too early, the sauce can thin back out and lose its shine. By the end, the liquid should coat the back of a spoon and look silky instead of cloudy.

What to Change When You Need a Different Version

Answers to the Questions Worth Asking

Crockpot Pepper Steak with Peppers and Onions

Crockpot pepper steak with peppers and onions delivers fork-tender beef and a glossy savory sauce with colorful bell peppers and sweet onions. Slow-cooked low-and-slow, it’s ready to spoon over rice or noodles for an easy weeknight meal.

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Prep Time 15 minutes mins

Cook Time 6 hours hrs 30 minutes mins

Total Time 6 hours hrs 45 minutes mins

Servings: 6 servings

Course: Dinner

Cuisine: American

Calories: 430

Ingredients Equipment Method Notes

Ingredients

  

beef sirloin or flank steak

• 2 lb beef sirloin or flank steak thinly sliced

cornstarch

• 2 tbsp cornstarch for tossing the beef

olive oil

• 2 tbsp olive oil

yellow onion

• 1 yellow onion large, sliced

green bell peppers

• 2 green bell peppers sliced

red bell pepper

• 1 red bell pepper sliced

garlic

• 3 cloves garlic minced

low-sodium beef broth

• 1 cup low-sodium beef broth

low-sodium soy sauce

• 0.25 cup low-sodium soy sauce

Worcestershire sauce

• 2 tbsp Worcestershire sauce

brown sugar

• 1 tbsp brown sugar

ground black pepper

• 1 tsp ground black pepper

smoked paprika

• 0.5 tsp smoked paprika

onion powder

• 0.5 tsp onion powder

crushed red pepper flakes

• 0.25 tsp crushed red pepper flakes optional

cold water

• 2 tbsp cold water for cornstarch slurry

chopped fresh parsley

• 1 chopped fresh parsley for garnish

cooked white rice

• 6 cooked white rice for serving

Equipment

• 1 Dutch oven

Method

 

Prep and sear the beef

1. Toss the thinly sliced beef sirloin or flank steak with 2 tbsp cornstarch until lightly coated, so every strip has a thin, even dusting.
2. Heat 2 tbsp olive oil in a large skillet over medium-high heat, then sear the beef for 2–3 minutes until lightly browned.
3. Transfer the seared beef to the crockpot, keeping any browned bits in the skillet for flavor if they cling to the beef.

Cook with peppers, onions, and sauce

1. Add the sliced yellow onion, green bell peppers, red bell pepper, and minced garlic over the beef.
2. Whisk together 1 cup low-sodium beef broth, 1/4 cup low-sodium soy sauce, 2 tbsp Worcestershire sauce, 1 tbsp brown sugar, 1 tsp ground black pepper, 1/2 tsp smoked paprika, 1/2 tsp onion powder, and 1/4 tsp crushed red pepper flakes, then pour the sauce over everything.
3. Cover and cook on Low for 6–7 hours or High for 3–4 hours, until the beef is fork-tender and the peppers are tender-crisp.

Thicken the sauce and serve

1. Mix the remaining 1 tbsp cornstarch with 2 tbsp cold water to form a smooth slurry.
2. Stir the slurry into the crockpot during the last 20 minutes of cooking, then continue cooking until the sauce thickens and becomes glossy.
3. Garnish with chopped fresh parsley and serve hot over cooked white rice.

Notes

For the most tender slices, keep the beef thin and avoid overcooking on High—once it’s fork-tender, thicken right away with the cornstarch slurry. Store leftovers in the refrigerator up to 4 days in a sealed container. Freeze up to 2 months, then reheat gently on the stovetop or in the microwave until hot. For a lower-carb option, serve over cauliflower rice instead of white rice.