Slow Cooked Pho Broth
By Emma
Certified Culinary Professional
•
Recipe tested & approved
Bone broth simmered long for pho. Roasting bones to brown, spices toasted dry, onions and ginger charred. Slow simmer locks in flavors, flan beef added late for fresh texture. Strained, sweetened slightly, seasoned to taste. Layer of fat can be skimmed or left for richness. Swap star anise for cardamom for warmth twist. Adjust cook times by aroma and color changes. Utilizes slow cooker for ease, oven roast concentrates flavors. Adapt spices for preference. Clear, fragrant broth base for assembling pho with fresh herbs and noodles.
Prep:
20 min
Cook:
Total:
Servings:
14 servings
#Vietnamese
#broth
#slow cooked
#pho
#bone broth
#simmer
#slow cooker
#roast
#spices
Bones roasting in the oven, that sizzling sound before the aroma even hits you, it’s the start of everything—rich broth. Toasted coriander and fennel seeds crackle in dry pan releasing bursts of warm perfume. Onions and ginger catch fire slightly, that char adds shadows in the flavor—a bitterness balancing the beefy depth. The slow cooker hums quietly while hours tick away, broth darkens, thick with goodness you can smell and almost taste through the kitchen air. Adding flank beef late keeps texture alive, not overcooked mush. Skimming the fat after slows it down, or leave it in for velvety mouthfeel. Tried with cardamom last batch, unexpected twist but rounded warmth that lingers. This broth screams patience but rewards every single minute.
Ingredients
- 2.1 kg marrow beef bones
- 25 ml coriander seeds
- 12 ml fennel seeds
- 3 whole cloves
- 1 cinnamon stick 4.5 cm length
- 1 cardamom pod (replace star anise for twist)
- 2 onions halved unpeeled, rinsed
- 2 pieces ginger 5 cm length halved, unpeeled, rinsed
- 3.5 liters water
- 12 ml salt
- 190 g flank beef
- 15 ml raw cane sugar
About the ingredients
Marrow bones best for gelatin, but short ribs or knuckles work in a pinch. Marrow’s richness boosts mouthfeel; avoid frozen bones for better roast due to less water leakage. Replacing star anise with cardamom pod adds a subtle citrusy warmth, shift flavor profile without overpowering. Onion and ginger skins left on for deeper color and slight earthiness, but scrub clean. Water filtered or bottled for clarity—tap water sometimes dulls flavors or causes cloudiness. Cane sugar smooths sharp edges; brown sugar or honey work but affect sweetness differently. Salt is flexible; sea salt preferred but kosher or table salt okay—adjust accordingly. Flank beef chosen thin and fibrous, holds up in broth texture; brisket or chuck thin slices as alternatives. Props: cheesecloth bag keeps spices contained—helps filtration later, no grit in broth.
Method
- Position oven rack center. Preheat oven to 205°C 400°F. Place bones in roasting pan spaced out. Roast 55-65 min until golden brown and fragrant. Watch edges turn caramelized but no black spots. Browned bones equal deeper broth.
- Meanwhile toast coriander and fennel seeds in dry pan medium-high heat, shaking often till aromatic and dark golden, about 2-3 min. Remove to plate. In same pan add cloves, cinnamon, cardamom pod; stir till spices start to blister and smell toasted, about 1-2 min. Transfer spices to cheesecloth bag tied with kitchen string.
- Char cut sides of onion and ginger in hot dry pan on high. Flip to scorch skin and get smoky aroma; should sizzle but not burn entirely. This step adds that subtle bitterness and depth to broth.
- Transfer roasted bones to slow cooker. Add charred onion, ginger, cold water covering bones by at least 2 cm. Sprinkle salt evenly. Set cooker high heat setting. Cook 6 hours minute variations don’t kill it. Look for broth turn deep amber, skim surface foam occasionally.
- After 6 hours add flank beef and spice bag. Cover and cook 1 hour more. Beef releases gelatin and mellows broth. Touch flank to feel firmness; cooked but not falling apart.
- Remove flank with tongs; rinse quickly under cold water to stop cooking. Pat dry on paper towels. Slice thin against grain when cool enough. Reserve for Pho serving assembly.
- Strain broth through fine mesh strainer into clean pot. Discard bones, spices, onion, ginger. Add cane sugar. Taste and adjust salt and pepper. If broth too intense, add small water to mellow. If dull, roast extra onion and add back.
- Let broth cool slightly. A fat cap will rise. Skim partially to lighten if preferred or stir in for richness before serving.
- Broth can be chilled covered up to 3 days. Reheat gently. For convenience, roast bones night before and start slow cooker in morning. Saves active cook time.
Cooking tips
Don’t rush roast bones—browning is key to complex broth, char that marks umami foundation. Smell key indicator—nutty and toasted till brown but no burnt smell. Dry toast spices in low to medium heat, prolonging to prevent bitterness; high heat blitz to burnt creates bad off notes. Onions and ginger scorching should be quick, almost smoking but watch for black char spots which turn bitter. Slow cooker settings vary—if broth smells weak after 5 hours, swap to high heat or add short burst roasting to bones then return. Skim gray scum early during cook to clarify. Flank beef timing critical—too long and it disintegrates, too short no gelatin release; aim for firm but tender. Strain through fine mesh twice if necessary. Adjust final salt with palate in mind, broth intensifies after refrigeration. Fat skim depends on preference; it traps aroma and mouthfeel but too much clogs clarity and heaviness. Store broth cooled, seal tight to avoid odor absorption.
Chef's notes
- 💡 Roast bones till deep golden but watch edges; caramelized means flavor depth but black spots turn bitter. Smell is best guide here—nutty, warm, no burnt sting. No shortcuts roasting, patience locked here.
- 💡 Dry toast spices in batches; coriander then fennel first, then cloves cinnamon cardamom all at once. Heat medium, shake or stir slow. Too fast, spices scorch—off notes kill broth aroma. Tying in cheesecloth bag keeps broth clean, no grit.
- 💡 Char onion and ginger cut sides quick on high; dark brown almost black spots bring slight bitterness balancing broth rich notes. Flip fast, smells smoky, sizzle signals right char. Avoid full burn or mushy soggy pieces.
- 💡 Slow cooker set high for initial 6 hours with bones, water, salt. Broth color dark amber, skim foam early early early. Swapping to low if weak aroma, or extra roast mid-cook if broth dull. Watch broth surface, not just time.
- 💡 Add flank beef late; 1 hour max. Too long and beef disintegrates; too short no gelatin released. Firm but tender texture crucial. Remove quickly cool, slice against grain thin for serving texture. Saves broth clarity from beef fat losses.
Common questions
Can I use frozen bones?
Not really. Frozen bones leak water, dilutes broth. Roast less brown too. Use fresh marrow bones better. Short ribs work if marrow not ready. Frozen just emergency.
What if broth cloudy?
Skim foam and gray scum early. Slow cook on high only if aroma weak. Cheesecloth bag essential. Sometimes double strain helps. Add roasted onion back if dull color.
Why add flank beef late?
Longer cook breaks meat to mush, broth heavy fat. Flank beef gives gelatin, tender bite without break down. Skim fat too after beef out or keep for velvety mouthfeel. Balance is subtle flair.
How to store broth?
Chill covered in pot or airtight container. Up to 3 days fridge; freeze if longer. Fat layer solidifies seal broth. Reheat gentle or dilute if too intense. Sometimes broth thickens in fridge, stir to reset.
