A steaming bowl of pho makes a quiet Sunday feel special, and a slow cooker keeps the broth simple to prepare. Add the bones, spices, and aromatics, then let steady heat build a rich, fragrant flavor while you get on with your day.
You’ll have a generous batch for about six to eight bowls, with extra broth to freeze for another meal.
Why Make Pho Broth in a Slow Cooker?
Traditional pho broth takes hours of simmering and attention. A slow cooker holds a gentle, even temperature, which helps draw flavor from the bones and spices without a hard boil.
The result is a clear, aromatic broth with very little hands-on work. Start it in the morning or before bed, then prepare your noodles and toppings when you’re ready to eat.
Ingredients That Build Pho Flavor
Beef marrow and knuckle bones give the broth body, while charred onion and ginger add a lightly smoky sweetness. Star anise, cinnamon, cloves, coriander, and fennel bring the familiar warm spice aroma.
Fish sauce adds savory depth, and a little sugar balances the flavor. Garlic and black cardamom are optional, but both add another layer to the broth.
Read through the steps before you begin, then let the slow cooker handle most of the work.
Ingredients
- 3 to 4 pounds beef bones, preferably a mix of marrow and knuckle bones
- 1 large onion, halved
- 1 large piece fresh ginger, about 4 inches long, halved lengthwise
- 4 star anise pods
- 1 cinnamon stick
- 4 whole cloves
- 1 tablespoon coriander seeds
- 1 teaspoon fennel seeds
- 3 tablespoons fish sauce, plus more to taste
- 1 tablespoon rock sugar or brown sugar
- 1 tablespoon salt
- 12 cups cold water
- Optional: 1 black cardamom pod, 2 garlic cloves, or 1 teaspoon white peppercorns
How to Make Slow Cooker Pho Broth
- Parboil the bones. Put the beef bones in a large pot and cover them with cold water. Bring to a boil and cook for about 10 minutes. Drain, then rinse the bones under warm water to remove residue and help keep the broth clear.
- Char the onion and ginger. While the bones boil, place the onion and ginger cut-side down in a dry skillet over medium-high heat. Cook for 5 to 8 minutes, until the cut surfaces are dark in spots and fragrant.
- Toast the spices. Add the star anise, cinnamon, cloves, coriander seeds, and fennel seeds to the skillet. Toast for 1 to 2 minutes, moving them around so they become fragrant without burning.
- Fill the slow cooker. Add the rinsed bones, charred onion and ginger, toasted spices, fish sauce, sugar, salt, and any optional ingredients. Pour in the cold water, making sure the bones are covered.
- Cook the broth. Cover and cook on low for 8 to 10 hours, or on high for 5 to 6 hours. Avoid stirring, since moving the ingredients around can make the broth cloudy.
- Strain and season. Carefully strain the broth through a fine-mesh sieve lined with cheesecloth. Discard the solids, then taste the broth and add more fish sauce or salt as needed.
- Skim and store. For easier skimming, chill the broth and lift off the solidified fat. You can also skim excess oil from the surface while the broth is hot. Refrigerate for up to four days or freeze for up to three months.
How to Serve Pho
Prepare rice noodles according to the package directions, then divide them among serving bowls. Add thin slices of raw beef and pour hot broth over the top so the meat cooks gently, or use cooked beef for an easier option.
Set out Thai basil, cilantro, mint, bean sprouts, lime wedges, sliced chilies, hoisin, and sriracha. Everyone can add the toppings they like.
For a lighter broth, use chicken bones and shorten the cooking time slightly. You can also add mushrooms and bok choy for a vegetable-forward bowl, or adjust the spices to suit your taste.
A drizzle of chili oil or a few extra slices of onion adds a bright finish.
Tips for Clear, Flavorful Broth
Start with cold water to help draw flavor from the bones gradually. If you’re nearby during the first hour, skim any foam that rises to the surface for a cleaner broth.
Add fish sauce gradually and taste as you go, since its saltiness varies by brand. If you want a deeper, more roasted flavor, cook the bones on a baking sheet at 400°F for 30 minutes before adding them to the slow cooker.
That extra step is optional, and the broth will still be fragrant and satisfying without it.
Make Pho Broth Ahead
Slow cooker pho broth takes patience, but it doesn’t require much attention. With beef bones, toasted spices, and a few fresh aromatics, you can prepare a flavorful base for Sunday lunch or an easy weeknight dinner.
Make a full batch and freeze what you don’t use. The next time you want pho, warm the broth, prepare the noodles, and set out your favorite toppings.
Food writer and passionate home cook dedicated to creating easy, delicious recipes, quick weeknight meal ideas, and practical kitchen tips. Focused on helping everyday cooks recreate wholesome, flavorful dishes at home with simple ingredients and clear, step-by-step guides.