Mornay onion tart


Mornay onion tart
In a shortcrust pastry base, a rather thick onion tart, where onions and lardons are deliciously bound with a Mornay sauce.
29 K 4.9/5 (28 reviews)
Grade this recipe:
Keywords:
Last modified on: June 23th 2024
For this recipe: Comment Send to a friend Ask me a question Follow Printable Diaporama Video
For 6 people, you will need:

Change to the quantities for:
Change measures:
Times for this recipe
Preparation: 1 hour 3 min.
Cooking: 1 hour 15 min.
All in all: 2 hours 15 min.
When should you start or finish this recipe?
If you start now, at , you will finish around : ?.Change start time
To finish around 7pm, you'll need to have started before: .Change end time

Step by step recipe


Stage 1 - ⌛ 20 min.
Mornay onion tart : Stage 1
Roll out 300 g shortcrust pastry (pâte brisée) then line a 22 cm (9-inch) diameter high-sided baking tin, which you will have placed on a sheet of baking paper in a baking tray.

Leave any excess dough around the edges, then place in the fridge to set aside.

Stage 2 - ⌛ 10 min.
Mornay onion tart : Stage 2
Prepare and slice 1 kg onion (a mandolin is ideal for this).
This may seem like a lot, but don't worry, they'll reduce when cooked.

Stage 3 - ⌛ 3 min.
Mornay onion tart : Stage 3
In a large saucepan over medium heat, melt 50 g butter, and when hot, add the onions.

Season with salt and stir well.

Cover for the first 5 minutes.

Stage 4 - ⌛ 10 min.
Mornay onion tart : Stage 4
Leave to cook until the onions are tender, checking the salt seasoning as cooked onions tend to be a little sweet.

Stage 5 - ⌛ 5 min.
Mornay onion tart : Stage 5
Your onions should be fairly dry, with little or no cooking juices.
If this isn't the case, because they've given off a lot of water during cooking, drain them in a fine sieve.

Set aside.

Stage 6 - ⌛ 3 min.
Mornay onion tart : Stage 6
Preheat oven to 200°C (390°F).

Cut 150 g smoked pork belly (or thick cut streaky bacon) into small pieces.

Stage 7 - ⌛ 8 min.
Mornay onion tart : Stage 7
Toast them, without adding fat, in a small frying pan over medium heat.

Stage 8 - ⌛ 1 min.
Mornay onion tart : Stage 8
When toasted to your liking, add 4 tablespoons vinegar, and stir until evaporated.

Stage 9 - ⌛ 2 min.
Mornay onion tart : Stage 9
It's not essential, but I recommend adding 2 or 3 spoonfuls of already-cooked onions to the pan at the end of cooking, then stirring well to capture all the flavor of the grilled bacon.

Stage 10 - ⌛ 2 min.
Mornay onion tart : Stage 10
Pour the lardons + onions into the remaining onions and mix well.

Stage 11 - ⌛ 2 min.
Mornay onion tart : Stage 11
Add 300 g mornay sauce and mix well.

Stage 12 - ⌛ 20 min.
Mornay onion tart : Stage 12
Take the pastry mould out of the fridge, cut the excess pastry around the edges of the mould, place a sheet of baking paper on the bottom and fill with ceramic balls (or similar).

Bake at 200°C (390°F) for 20 minutes.

Stage 13 - ⌛ 5 min.
Mornay onion tart : Stage 13
In the meantime, you can roll out the pastry scraps into small strips to decorate the tart.

Stage 14 - ⌛ 1 min.
Mornay onion tart : Stage 14
After 20 minutes, remove the baking tray from the oven...

Stage 15 - ⌛ 5 min.
Mornay onion tart : Stage 15
... and remove paper and beads.

Stage 16 - ⌛ 2 min.
Mornay onion tart : Stage 16
Fill the tart with the onion-lardon-Mornay mixture.

Stage 17 - ⌛ 2 min.
Mornay onion tart : Stage 17
If you have made some, place the pastry strips on top.

Stage 18 - ⌛ 3 min.
Mornay onion tart : Stage 18
Sprinkle with a little grated cheese.

Stage 19 - ⌛ 30 min.
Mornay onion tart : Stage 19
Bake for a further 30 minutes.

Stage 20
Mornay onion tart : Stage 20
Enjoy warm or hot, on its own or with a small green salad.
Remarks
If you find your onions a little too soft at the end of cooking, you can add a good glass of dry white wine.

If you don't have a Mornay sauce, use a Béchamel sauce to which you can add grated cheese to taste.

You'll notice that in this recipe, the onions are cooked without coloring, but if you prefer, you can caramelize them. In this case, increase the weight of onions to 1.5 kg, as they will reduce even more.
Keeping: 1 or 2 days in the fridge, protected by cling film.
Source: Home made.
Nutritional information
Proteins (gr)Carbohydrates (gr)Fats (gr)Energy value (in k-calories)Energy value (in k-joules)
Whole recipe360 RDI=140 %1,490 RDI=140 %1,280 RDI=200 %3,420 RDI=170 %14,320 RDI: 170 %
Per 100 g20 RDI=7 %80 RDI=7 %70 RDI=10 %180 RDI=9 %760 RDI: 9 %
Per person60 RDI=20 %250 RDI=20 %210 RDI=30 %570 RDI=30 %2,390 RDI: 30 %
The % figures are calculated in relation to the Recommended Dietary Intake , or RDI of 2,000 k-calories (or 8,400 k-joules) per day for a woman
Possible allergens in this recipe: Gluten, milk, egg, Sulfites
How much will it cost?
  • For 6 people : 5.40 €
  • Per person : 0.90 €

Change currency:

Note: Be careful, these prices are only an estimate, you can consult the table of prices by ingredients used for this estimate.
This recipe uses (among others)
Other recipes you may also like
How to cook Morteau sausage well
How to cook Morteau sausage well
This is, in my opinion, the best smoked sausage. You can cook it in a number of ways, here are three of the best known.
November 15th 20182.81 M 23.4 40 min.
Chocolate mendiants
Chocolate mendiants
Mendiants are made with a thin layer of chocolate, stuck with toasted nuts, dried and candied fruit.
May 27th 202063 K 1 hour 2 min.
Hot sesame-cream chicken tartines
Hot sesame-cream chicken tartines
Slices of lightly toasted bread topped with sesame and tarragon cream, morsels of chicken and a little grated cheese. Just popped in the oven for a few minutes to brown. [Translator's note: in French, a tartine is simply a slice of bread spread with something (butter, jam...) or an open sandwich, sometimes hot. The term is now catching on in English.].
January 22th 202048 K 30 min.
Basic cake batter - the French way
Basic cake batter - the French way
The cake is one of the classic cakes of the pastry world (The frenchs call them "journey cake"), and there are many ways to make it. Here's a new basic recipe for its dough, into which you can then add the flavors (pistachio, lemon, chocolate, etc.) and ingredients (dried fruit, fresh fruit, etc.) of your choice.
September 7th 202563 K 20 min.
Pasta with cherry tomatoes, olives and feta cheese
Pasta with cherry tomatoes, olives and feta cheese
Here's a super-simple, but simply delicious recipe, where pasta, cooked separately, is mixed with a kind of cream made from cherry tomatoes, black olives and feta cheese, baked in the oven. You'll find that the taste, and the creamy texture of pasta prepared in this way is simply amazing.
August 27th 202335 K 20 min.
News list of cooking-ez.com

Sign up to receive the latest recipes (next batch due to be sent on 2025-12-14)

*Your e-mail Your first name or nickname
I am not a leaving thing
Note: We'll never share your e-mail address with anyone else.
Post a comment or question
Posted by:
I am not a leaving thing

Follow this recipe
If you are interested in this recipe, you can "follow" it, by entering your email address here. You will then receive a notification immediately each time the recipe is modified or a new comment is added. Please note that you will need to confirm this following.
I am not a leaving thing
Note: We'll never share your e-mail address with anyone else.
Alternatively: you can subscribe to the mailing list of cooling-ez.com , you will receive a e-mail for each new recipe published on the site.

Back to top of page