Blooming Onion

Name: Blooming Onion
Prep time: 20 min
Cook time: 10 min
Total time: 30 min
Ingredients: 2 Brown (Yellow) Onions (Large); Vegetable, Canola or Sunflower Oil For Frying; 150 g Plain Flour (All Purpose); 4 g Cornflour (Cornstarch); 4 g Ground Cumin; 4 g Smoked Paprika; Salt & Pepper (To Taste); 1 Egg; 250 ml Full Fat Milk; 1 Egg (You Can Use Pasteurised If Needed); 180 ml Neutral Oil; 7.5 ml White Vinegar or Lemon Juice; 5 g Dijon Mustard; Salt & Pepper (To Taste); Mayonnaise (Above); 15 g Tomato Ketchup; 15 g Horseradish; 15 ml Worcestershire Sauce; 4 g Smoked Paprika; 4 g Garlic Powder; 2 g Red Chilli Powder (Optional); Salt & Pepper (To Taste)

PREP

20 mins

COOK

10 mins

SERVES

DIFFICULTY

Medium

↓ Jump to Recipe

Chef Jack Ovens

Qualified Chef · 1.63M Subscribers

Updated August 2026

A proper blooming onion is all about the cut. Slice it right and the petals fan out into layers that crisp up individually once they hit the oil, rather than turning into one soggy lump.

The double dredge is what gets you that thick, extra-crunchy coating — flour, then egg wash, then back into the flour again, working it into every single layer. It takes a bit of patience but it’s worth it.

Serve it hot straight out of the oil with the tangy Outback-style mayo for dipping. It’s a proper sharing starter and always goes down well at a table.

Blooming Onion

APPETISER · SHARED · MEDIUM

Why You'll Love This Blooming Onion

Crispy, golden, and made completely from scratch

Cutting the onion evenly is what makes it bloom open properly. Take your time with it and every petal cooks at the same rate, instead of some staying raw while others burn.

The double dredge and a properly hot oil are what give you that thick, crunchy coating without it turning greasy. Keep the oil at temperature and it crisps up fast instead of soaking up excess oil.

And the tangy mayo isn't an afterthought here — it's made properly from scratch, with a punchy horseradish and Worcestershire kick that cuts right through the richness of the fried coating.

Blooming Onion

Print Recipe

5 from 1 vote

Prep Time: 20

Cook Time: 10

Total Time: 30

Calories: 600kcal

Servings: People

Metric - Imperial

Ingredients

Onion & Oil

2 Brown (Yellow) Onions Large
Vegetable, Canola or Sunflower Oil For Frying

Flour Mixture

150 g Plain Flour All Purpose
4 g Cornflour Cornstarch
4 g Ground Cumin
4 g Smoked Paprika
Salt & Pepper To Taste

Egg Wash

1 Egg
250 ml Full Fat Milk

Mayonnaise

1 Egg You Can Use Pasteurised If Needed
180 ml Neutral Oil
7.5 ml White Vinegar or Lemon Juice
5 g Dijon Mustard
Salt & Pepper To Taste

Tangy (Outback Style) Mayonnaise

Mayonnaise Above
15 g Tomato Ketchup
15 g Horseradish
15 ml Worcestershire Sauce
4 g Smoked Paprika
4 g Garlic Powder
2 g Red Chilli Powder Optional
Salt & Pepper To Taste

Method

Mayonnaise

Place all of the mayonnaise ingredients into a tall jar or container. Blend with an immersion blender until thick and creamy. Transfer to a bowl.
Add the tangy (Outback-style) ingredients, mix to combine, and place in the fridge until ready to serve.

Blooming Onion

Preheat a deep fryer, or fill a large high-rimmed pan or pot with enough oil to fill it by half, and heat to 170°C (340°F).
Peel and remove the tip from the onion, leaving the root intact. With the root facing up, slice next to the root to create 4 even slices around the onion in a cross shape. Slice in between each original slice to create 16 even-sized slices all the way around. Flip the onion over and gently open it to create a blooming onion (see photo and video).
Add all the flour mixture ingredients to a bowl and mix to combine.
In a separate bowl, whisk together the egg and milk to create an egg wash.
Dust the blooming onion in the flour mixture, making sure each individual layer is well coated.
Transfer the onion into the egg wash and coat well.
Place the egg-washed onion back into the flour, making sure everything is completely covered, getting in between each layer.
Gently place the dredged onion into the preheated oil and fry for 6-7 minutes, or until golden brown and extremely crispy. Remove and drain over a wire rack or paper towel.
Serve the crispy golden blooming onion alongside the tangy mayonnaise. Dig in.

Chef's Tips

Take your time slicing the onion into even layers — uneven cuts mean some petals cook faster than others, and the onion won't "bloom" open evenly.

Double dredge the onion (flour, egg wash, then flour again) and really work the coating into every layer — this is what gives it that thick, extra-crispy crust.

Don't overcrowd the oil or fry at too low a temperature — keep it at 170°C (340°F) so the onion crisps up quickly rather than absorbing excess oil.

Storage & Reheating

This is best eaten fresh and hot, as the crispy coating won't hold up well once stored. If needed, leftovers will keep in the fridge for up to 2 days; reheat in the oven or air fryer at 180°C (350°F) until hot through and crispy again, rather than the microwave, which will make the coating soggy. Because the mayonnaise contains raw egg, use a pasteurised egg where possible, especially for pregnant, elderly, very young, or immunocompromised eaters — it'll keep in the fridge for around 5-7 days rather than the couple of weeks you'd get from shelf-stable, store-bought mayo.

Serving 1OnionCalories 600kcalCarbohydrates 42.6gProtein 10.6gFat 43.7gSaturated Fat 6.5gPolyunsaturated Fat 5.89gMonounsaturated Fat 28.68gTrans Fat 0.1gCholesterol 89.4mgSodium 231.7mgPotassium 374.3mgFiber 2.6gSugar 7.9gVitamin A 181.93IUVitamin C 8.12mgCalcium 130mgIron 1.9mg

Common Questions

How do I stop the onion falling apart when I cut it?⌄

The key is leaving the root intact — that's what holds all the petals together once it's sliced. Cut slowly and evenly around the onion, and it'll open up into a proper bloom rather than falling apart.

Can I make the mayonnaise without raw egg?⌄

Use a pasteurised egg if you'd rather avoid raw egg altogether — it works exactly the same way in the blender. This is especially worth doing if you're serving anyone pregnant, elderly, very young, or immunocompromised.

Can I bake this instead of deep frying it?⌄

You can, but it won't get quite as crispy as deep frying. If you go this route, bake it at a high heat, around 220°C (430°F), and spray it well with oil first to help the coating crisp up.

Can I make the mayo ahead of time?⌄

Yes, it keeps in the fridge for 5-7 days in an airtight container thanks to the raw egg base, so it's a good one to make ahead. The onion itself is best fried and eaten fresh though, right before serving.

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2 thoughts on “Blooming Onion”

Kirsten
August 24, 2022 at 2:29 pm

Hi Chef!

The recipe calls for 1.5 teaspoons or 30 ml vinegar. I think 1 teaspoon is usually supposed to be 5 ml (~5 ml in the US and exactly 5 ml elsewhere). And 30 ml would be ~2 Tablespoons or ~1 fl oz in the US. So is this a typo? Or is it an international spoon issue?

I ask in part because I know Aussie Tablespoons are tricky for Americans since ours are ~15 ml and I believe yours are 20 ml (we Americans have 3 teaspoons in a Tablespoon while I think Aussies have 4).

We’re very attached to volume measures in the US, which I know is annoying and not logical, but my scale just isn’t very good at small amounts so I must use measuring spoons. I’m overall confused on this spoon issue. Can you clarify whether the vinegar is a typo and whether I understand Aussie spoons correctly?

Thank you so much for the recipe and the video! I appreciate your hard work, how clearly you explain things, and how delicious your recipes are. Thank you!

Reply
1. Chef Jack Ovens
  August 24, 2022 at 2:38 pm
  
  Hi Kirsten. I’m confused to as where you’re reading it saying 1 1/2 tsp to 30 ml. On my end it says to 15ml. Have you adjusted the amount of people the recipe serves on the calculator by any chance?
  
  I’ll look into it a little further but you are correct about 1 tsp being 5ml 😊
  
  Sorry for any confusion and thank you very much for your kind words. Glad you’ve been enjoying the recipes.
  
  Reply

5 from 1 vote

Blooming Onion

Blooming Onion

Crispy, golden, and made completely from scratch