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If my husband had to pick a favorite weeknight dinner, this slow cooker vegetable massaman curry make just take first place. Every time we go out for Thai food, and I mean every single time, he orders chicken massaman. If you’ve never had it before, it’s a rich coconut and peanut curry, usually made with potatoes and peanuts. It’s luscious and creamy with a spicy peanut sauce that’s to die for.  I don’t fault him at all for being so predictable, because if he didn’t order it I would. [New Video below!]

Overhead shot of the massaman curry in a slow cooker.

Thai vegetable massaman curry

When I was writing my new book, Fresh Flavors for the Slow Cooker, I set out to recreate the flavors of James’s favorite Thai dish but in a lighter, fresher and easier fashion. I swapped out the chicken for cauliflower and green beans, but kept the potatoes, which soak up the sauce and give the curry substance. I also lightened up the curry base, using store-bought curry paste for ease and cutting back on the coconut milk. I’m happy to report that the recipe made it into the book (page 31: Thai Vegetable and Peanut Curry ?) and is now firmly part of our dinner rotation! The succulent vegetables soak up the silky sauce for a dynamic, healthy meal that we all adore.

How to make a vegetarian slow cooker Thai curry

The base for this curry is made with red curry paste, onion, garlic and ginger. The aromatics need a quick stint on the stovetop or in the microwave to soften before going into the slow cooker, but you can knock out this step a day ahead. The cooked aromatics go into the slow cooker with canned tomatoes, broth, flavorings (fish sauce, tamari and a touch of brown sugar), cauliflower and potatoes. Once the vegetables have simmered for several hours and are tender, a mix of coconut milk and peanut butter is added, lending the sauce creaminess and flavor. Frozen green beans are also added for color and brightness (see substitution ideas below), along with roasted peanuts, which are traditional and provide texture. 

Process shot divided into 4 quadrants, showing how to assemble the ingredients for the massaman curry in the slow cooker.
Process shot divided into 4 quadrants showing how to finish the curry in the slow cooker.

How do you serve massaman curry?

We serve this massaman curry over rice with both forks and spoons (you’re going to want to slurp up that sauce!). Serve the curry with chopped cilantro and peanuts for sprinkling, along with extra sriracha for those who like it spicy. It’s a flavor- and texture-packed one-bowl meal that’s comfort food at its best. 

Overhead shot of two bowls of massaman curry on a countertop, with peanuts and cilantro alongside for sprinkling.

Substitutions you can make in this recipe:

  • Swap out potatoes for diced butternut squash.
  • Swap out the frozen green beans for a few handfuls of spinach or frozen peas.
Overhead shot of bowl of curry with the book, Fresh Flavors for the Slow Cooker, alongside.

Tips for this easy massaman curry recipe:

  • 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!
Book cover of Fresh Flavors for the Slow Cooker.

More slow cooker recipes to try:

Watch the video!

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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 mins
Cook Time3 hrs
Total Time3 hrs 30 mins
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 1/2 pounds), cut into 2-inch florets
  • 1 pound red potatoes (about 3 medium potatoes), cut into 1-inch pieces
  • 1/2 cup canned coconut milk, well stirred
  • 1/2 cup creamy peanut butter
  • 2 cups frozen cut green beans
  • 1/3 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!

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