Mornay onion tart
In a shortcrust pastry base, a rather thick onion tart, where onions and lardons are deliciously bound with a Mornay sauce.
27 K 4.9/5 (28 reviews)
2 hours 15 min.
Easy
6 people
7 IngredientsLast modified on: June 23th 2024
For 6 people, you will need:
- 1
300 g shortcrust pastry (pâte brisée) - 2
1 kg onion - 3
50 g butter - 4
150 g smoked pork belly (or thick cut streaky bacon) - 5
4 tablespoons vinegar - 6
300 g mornay sauce - 7
30 g grated cheese - Total weight: 1,890 grams
Change measures:
Times for this recipe
Preparation: 1 hour 3 min.
Cooking: 1 hour 15 min.
All in all: 2 hours 15 min.
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.
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.
Leave any excess dough around the edges, then place in the fridge to set aside.
Stage 2 - 10 min.
Stage 3 - 3 min.
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.
Season with salt and stir well.
Cover for the first 5 minutes.
Stage 4 - 10 min.
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.
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.
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.
Preheat oven to 200°C (390°F).
Cut 150 g smoked pork belly (or thick cut streaky bacon) into small pieces.
Cut 150 g smoked pork belly (or thick cut streaky bacon) into small pieces.
Stage 7 - 8 min.
Toast them, without adding fat, in a small frying pan over medium heat.
Stage 8 - 1 min.
When toasted to your liking, add 4 tablespoons vinegar, and stir until evaporated.
Stage 9 - 2 min.
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.
Pour the lardons + onions into the remaining onions and mix well.
Stage 11 - 2 min.
Add 300 g mornay sauce and mix well.
Stage 12 - 20 min.
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.
Bake at 200°C (390°F) for 20 minutes.
Stage 13 - 5 min.
In the meantime, you can roll out the pastry scraps into small strips to decorate the tart.
Stage 14 - 1 min.
After 20 minutes, remove the baking tray from the oven...
Stage 15 - 5 min.
... and remove paper and beads.
Stage 16 - 2 min.
Fill the tart with the onion-lardon-Mornay mixture.
Stage 17 - 2 min.
If you have made some, place the pastry strips on top.
Stage 18 - 3 min.
Sprinkle with a little grated cheese.
Stage 19 - 30 min.
Bake for a further 30 minutes.
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.
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 recipe | 360 RDI=140 % | 1,490 RDI=140 % | 1,280 RDI=200 % | 3,420 RDI=170 % | 14,320 RDI: 170 % |
| Per 100 g | 20 RDI=7 % | 80 RDI=7 % | 70 RDI=10 % | 180 RDI=9 % | 760 RDI: 9 % |
| Per person | 60 RDI=20 % | 250 RDI=20 % | 210 RDI=30 % | 570 RDI=30 % | 2,390 RDI: 30 % |
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)
Onion
Like these other recipes: Endive and beer soup, Celery risotto, Mussels with arroz negro, Pollack Parmentier, Individual creamy endive gratins, ... See them all 148
Shortcrust pastry (pâte brisée)
You can get more informations, or check-out other recipes which use it, for example: Potato and cheese pie, Salmon and spinach quiche, Quiche Lorraine, Angevin plum pâté, Rata-tart, ... See them all 16
Mornay Sauce
You can get more informations, or check-out other recipes which use it, for example: Manou's zucchinis garnished, Small green vegetables in Mornay sauce, Eggs Florentine, Spinach Mornay, ... See them all 4
Smoked pork belly (or thick cut streaky bacon)
Like these other recipes: Soup Cornouaillaise, Boeuf (beef) bourguignon, Warm lentil salad, Dandelion salad, New Zealand pies, ... See them all 6
Other recipes you may also like
Welsh (French Welsh Rarebit)
This is a French version (as served in brasseries in northern France) of the traditional Welsh rarebit. It contains boiled ham as well as the usual toasted bread and Cheddar cheese melted in beer. February 2nd 2014109 K4.2 35 min.
Apple confectioner's custard
For this strongly apple-flavoured version of confectioner's custard (crème pâtissière, or french pastry cream), apple juice is used instead of milk and the quantity of sugar is reduced. July 23th 2014147 K4.6 25 min.
How to peel hazelnuts
The skin of whole hazelnuts, unlike that of almonds, doesn't improve their taste - on the contrary. So you need to remove it before using them, and here's how. August 4th 202424 K
Apple syrup
Here's how to make a simple, no-sugar-added apple syrup that can be used in other recipes, for its taste and/or to replace sugar. March 23th 202513 K 35 min.
Chestnut cake
This delightful cake is doubly chestnutty: it contains chestnut flour, and sweet chestnut purée. August 28th 2025351 K5 1 hour 15 min.
News list of cooking-ez.com
Sign up to receive the latest recipes (next batch due to be sent on 2025-10-12)
Note: We'll never share your e-mail address with anyone else.
Post a comment or question
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.
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.