A tasty “old School” cheese and onion flan recipe made with just four main ingredients (and a couple of optional extras!) Serve this delicious cheese pie with salad, chips or baked beans!

I posted a picture of this cheese and onion flan on my social media yesterday and the post went a little bit nuts! I had lots and lots of requests for the recipe.
I’m such a fan of old fashioned recipes and collect old cookbooks. I’ve been re-reading books from the 80’s and 90’s lately and I saw a recipe for cheese flan.
old school cheese and onion flan
The sight of this old fashioned dish conjured up memories of School dinners for me. I didn’t really eat lunch at School until I was in secondary school, but I immediately recognised this cheese flan. I remember having it with baked beans and for pudding, a slice of retro School dinner cake!
I will admit that my version isn’t exactly school dinner style. I can’t imagine the dinner ladies having time to blind bake pastry. I always take the time to bake the pastry case first before adding the filling – I can’t stand a soggy bottom!
why you should try this recipe
- It’s cheap to make
- uses basic store cupboard ingredients
- family friendly
- it’s not only great for dinner – it’s lovely for lunch and great for popping in lunchboxes
- can be eaten hot or cold
ingredient list for cheese and onion flan
To make this recipe you will need:
shortcrust pastry.
For convenience, I used a block of ready made shortcrust to line the tin. As much as I prefer homemade pastry, I just didn’t have the time to make it this week. Shop bought pastry is a great shortcut if you’re in a hurry.
onion
I’ve noticed that a few cheese and onion flan recipes don’t instruct you to cook the onion before mixing it with the cheese, eggs and milk. I tried it this way and I have to say I’m not a fan. It’s much nicer if you soften the onions down with a little oil and butter first. I know it’s an extra thing to do, but in my view it’s well worth doing.
cheddar cheese
A strong flavoured cheese gives the best flavour. I use a mature cheddar cheese. I was using up what I had in my fridge, so I used a mixture of white and red cheddar.
milk
Whole milk or semi skimmed. I wouldn’t advise using skimmed milk – it’s far too thin. For a richer result, you could use cream instead of milk (but obviously not so budget friendly).
eggs
You’ll need two large eggs for this recipe.
salt and pepper
A little seasoning makes all the difference.
optional extra – mustard
It’s not essential to do so, but I added a teaspoon of English mustard to enhance the flavour of the cheese. I always use this trick in my cheese sauce for cauliflower cheese.
how to make cheese and onion flan
(keep scrolling to the end of the post to find a printable recipe card with ingredient amounts and detailed instructions)
Step one – Roll out the pastry on a lightly floured work surface. Line a 22 or 23cm pie or flan dish with the pastry, making sure the pastry is a little bit higher than the sides of the tin.
Trim and flute the edges or press them down with the back of a fork. Prick all over the bottom of the pastry with a fork. Place the tin in the fridge while you preheat the oven to 200C/180Fan and cook the onions. I try and chill pastry for a minimum of 20 minutes, if I have the time.
Step two – Place baking beans and a large piece of baking parchment in the chilled pastry case. No baking beans? Me neither! I use dried lentils and barley! You just have to be careful you don’t let them get on the pastry. Once baked, they add a crunchy texture that isn’t ideal….:-))
Blind bake the pastry case for about 15 minutes or until the crust is beginning to turn light golden, then remove the beans and paper and pop back in the oven for about 5 minutes until the bottom of the pastry is a little bit firmer.
Step three – On a low-medium heat, gently fry the onions in a butter and oil until they have softened but not coloured. This usually takes about 8-10 minutes.
Step four – Whisk the eggs and milk together well. Stir in the mustard and grated cheese along with salt and pepper. I go easy on the salt (since there’s salt in the cheese anyway) and heavier on the pepper. Stir in the cooked onions.
Step five – carefully pour the filling into the pastry case. Bake for 30-35 minutes at 180C/160Fan or until the filling has puffed up and is beautifully golden. The smell will make you very, very hungry.
serving cheese and onion pie
You could serve the flan warm or cold with a salad and chips or a baked potato on the side with maybe some creamy coleslaw. For a school dinner throwback, serve with chips and baked beans!
is a flan similar to a quiche?
They are very, very similar! Like a quiche, a savoury flan in the UK is really a pastry lined tart filled with an egg and milk filling and whatever else you want to throw in. This flan recipe has a slightly softer set than a quiche.
As I’ve already mentioned, some flan recipes don’t ask you to blind bake the pastry, giving a much softer crust.
If you would like to make this recipe without pre-baking the crust, I would recommend you roll the pastry out as thinly as you possibly can to prevent it from being soggy. But to be honest, it’s much better to blind bake!
more quiche recipes
variations
- Add some crispy chopped bacon or cooked ham
- Top the flan with sliced tomatoes
- use red onion or sliced spring onion instead of a white onion
storing leftovers
Any leftover flan should be stored in the fridge and used within three days. You can also freeze leftovers for up to three months.
did you make this recipe?
I really hope you love it! Please let me know what you thought by leaving a comment below and rate the recipe by clicking on the stars in the recipe card.
Cheese and Onion Flan
My version of an old school cheese and onion flan! Shortcrust pastry with lots of cheddar cheese and onions. This old fashioned favourite is cheap to make and tastes absolutely wonderful.
Ingredients
- 350g ready rolled or block of shortcrust pastry
- 1 tablespoon vegetable or olive oil
- 1/2 tablespoon butter
- one medium onion, peeled and finely diced
- 2 large eggs
- 150ml milk
- 1 teaspoon English mustard (optional)
- salt and pepper
- 175g mature cheddar cheese, grated
Instructions
- Preheat the oven to 200C/180Fan.
- LINE YOUR FLAN TIN. Roll out the shortcrust pastry on a lightly floured surface. Line a 22cm tart tin or flan dish with the pastry. Prick all over the bottom of the pastry with a fork.
- BLIND BAKE THE PASTRY CASE. Place a piece of baking paper and baking beans (I use dried barley) in the pastry case and bake in the oven for about 15 minutes or until the edges are light golden. Remove from the oven, remove the baking beans and paper and return to the oven for about 5 minutes. Remove the pastry case from the oven and set aside. Turn the oven temperature down to 180C/160Fan.
- COOK THE ONIONS. Some recipes add the raw onions straight into the pastry case which admittedly is much easier, but I'm not really a fan of undercooked, crunchy onions. Heat the oil and butter in a medium pan over a low medium heat, then add the diced onions. Sprinkle with a little bit of salt so they don't turn brown, then gently fry for 8-10 minutes or until softened. Remove from the heat and set aside to cool slightly.
- MAKE THE FILLING. In a medium bowl, beat the eggs and milk together and season with a little salt and pepper. Stir in the mustard (if using), grated cheese and onions.
- BAKE. Pour the filling into the pastry lined dish. Place in the oven and bake at 180C/160Fan for 30-35 minutes or until the filling has puffed up and looks golden. It might seem quite soft in the middle but will firm up as it cools down. Leave to cool slightly for about 20-30 minutes before slicing and serving with chips, salad or classic School dinner style - baked beans!
Notes
I've used bought shortcrust pastry for this recipe for convenience, but if you have a favourite home made pastry recipe feel free to use that instead.
VARIATIONS - Add some bacon - fry a few rashers until crispy before you cook the onions then cut up and add to the filling.
Top the flan with sliced tomatoes before baking.
Instead of a regular brown onion, you could use red or sliced Spring onions.
Nutrition Information:
Yield: 6 Serving Size: 1Amount Per Serving: Calories: 241Total Fat: 18gSaturated Fat: 9gTrans Fat: 0gUnsaturated Fat: 7gCholesterol: 103mgSodium: 342mgCarbohydrates: 10gFiber: 1gSugar: 4gProtein: 11g
Calories and nutritional information are provided by a third party application and should be viewed as indicative figures only.
This was a family favorite when I was growing up. I have made it a few times myself, but never wrote the recipe down when mum was still with us. This version was perfect and the addition of a little mustard (not in mum’s original) is defnitely worth it.
Hi Steve, I’m so pleased you like the recipe. Thanks for letting me know 🙂