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Close-up side view of vegetable massaman curry over rice in a serving bowl.
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Slow Cooker Vegetable Massaman Curry

Adapted from Fresh Flavors for the Slow Cooker: Reinvent the Slow Cooked Meal (Storey Publishing, 2019), by Nicki Sizemore. Whenever we go out for Thai food my husband orders chicken massaman, a rich coconut-based curry with meat, potatoes and peanuts. This lighter vegetable-packed curry takes inspiration from that dish, using peanut butter and coconut milk to thicken the sauce. It’s now one of James’s favorite weeknight meals—and mine too. Cauliflower and red potatoes give the curry heft, while frozen green beans, which are added at the end, impart brightness and color (you can use 3 cups of baby spinach in place of the green beans, if you prefer). Roasted peanuts also go right into the curry, providing texture (be sure to buy unsalted nuts). The aromatics need a quick stint on the stovetop before going into the slow cooker, but you can microwave them instead (instructions included!).
Prep Time30 minutes
Cook Time3 hours
Total Time3 hours 30 minutes
Course: Main Course
Cuisine: American
Keyword: easy thai vegetable curry, slow cooker vegetable curry recipe, vegetable massaman curry recipe
Servings: 6 people
Author: Nicki Sizemore

Ingredients

Aromatics

  • 1 tablespoon virgin coconut oil
  • 1 medium onion, finely chopped
  • 3 garlic cloves, minced
  • 1 tablespoon minced ginger
  • 2 tablespoons red curry paste

Slow cooker

  • 2 cups low-sodium vegetable or chicken broth
  • 1 (14.5 ounce) can diced tomatoes
  • 2 tablespoons fish sauce (preferably Red Boat brand)
  • 1 tablespoon tamari or soy sauce
  • 1 tablespoon packed brown sugar
  • 1 large head cauliflower (2 ½ pounds), cut into 2-inch florets
  • 1 pound red potatoes (about 3 medium potatoes), cut into 1-inch pieces
  • ½ cup canned coconut milk, well stirred
  • ½ cup creamy peanut butter
  • 2 cups frozen cut green beans
  • ⅓ cup roasted, unsalted peanuts
  • 1 tablespoon sriracha
  • Salt and freshly ground black pepper

For serving

  • Cooked rice or quinoa
  • Coarsely chopped peanuts
  • Chopped cilantro
  • Sriracha

Instructions

Start the aromatics

  • Heat the coconut oil in a medium skillet over medium-high heat. Add the onion, and season with salt and pepper. Cook, stirring occasionally, until slightly softened, about 3 minutes. Add the garlic, ginger and curry paste, and cook, stirring, until fragrant, 30-60 seconds. Scrape the mixture into a 4- to 7-quart slow cooker. (Alternatively, toss all of the ingredients together in a heatproof bowl and microwave on high, stirring occasionally, until softened, about 4 to 5 minutes.)

Assemble the slow cooker

  • Stir in the broth, tomatoes, fish sauce, tamari and brown sugar. Add the cauliflower and potatoes, and toss to coat. Cover and cook until the vegetables are tender, 5 to 6 hours on low or 3 to 4 hours on high.
  • Combine the coconut milk and peanut butter in a heatproof bowl and microwave until warm, about 1 minute (alternatively, you can warm them in a small pot on the stove); stir until smooth. Increase the slow cooker heat to high (if it’s not already). Pour the coconut milk mixture into the slow cooker, and add the green beans and peanuts. Cover and cook until warmed through, about 10 minutes. Add the sriracha, and season with salt and pepper.

Serve

  • Serve the curry over rice or quinoa, and sprinkle with chopped peanuts and cilantro. Serve with sriracha for drizzling.

Notes

Slow Cooker Jumpstarts:
Up to 2 days ahead:
  • Cook the aromatics and refrigerate.
  • Chop the cauliflower and potatoes and refrigerate separately (store the potato in water to prevent browning—drain before using).
Storage: The cooked curry can be refrigerated for up to 5 days or frozen for up to 3 months.
Tips:
  • You’ll need a 4- to 7-quart slow cooker (I use this 6-quart model, which I recommend) for this recipe. Different slow cookers cook at different rates, so use the times as an approximation. 
  • It won’t look like much liquid in the slow cooker at first with the vegetables, but the vegetables will release liquid as they cook (if you add too much liquid at the beginning the dish will be watered down).
  • Feel free to swap out the potatoes for cubed butternut squash and/or the green beans for a few handfuls of spinach. I use frozen green beans, which are pre-blanched, meaning they just need a few minutes to warm through in the curry. If you use fresh green beans, blanch them first in boiling water.
  • Be sure to use unsalted roasted peanuts in the curry (salted peanuts will be too salty).
  • The coconut milk and peanut butter are added at the end, giving the curry a creamy consistency (if added earlier they tend to separate).
  • Find a ton of other slow cooker recipes in my book, Fresh Flavors for the Slow Cooker!