Mornay onion tart
In a shortcrust pastry base, a rather thick onion tart, where onions and lardons are deliciously bound with a Mornay sauce.
12 K 5.0/5 (27 reviews)
2 hours 15 min.
Easy
18 people
7 IngredientsLast modified on: June 23th 2024
For 18 people, you will need:
- 1
900 g shortcrust pastry (pâte brisée) - 2
3 kgs onion - 3
150 g butter - 4
450 g smoked pork belly (or thick cut streaky bacon) - 5
12 tablespoons vinegar - 6
900 g mornay sauce - 7
90 g grated cheese - Total weight: 5,670 grams
Change measures:
Times for this recipe
Preparation: 1 hour 3 min.
Cooking: 1 hour 15 min.
All in all: 2 hours 15 min.
To finish around 7pm, you'll need to have started before: 17:20.Change end time
Step by step recipe
Stage 1 - 20 min.
Roll out 900 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 150 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 450 g smoked pork belly (or thick cut streaky bacon) into small pieces.
Cut 450 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 12 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 900 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 | 1,080 RDI=410 % | 4,480 RDI=420 % | 3,850 RDI=580 % | 10,260 RDI=510 % | 42,950 RDI: 510 % |
| 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 18 people : 16.15 €
- 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: Vegetable stock, Cured Pork Belly With Lentils, Stuffed tomatoes and courgettes, Pan-baked hash brown (Hash-brown casserole), Express sauerkraut, ... See them all 148
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, Spinach Mornay, Eggs Florentine, ... See them all 4
Shortcrust pastry (pâte brisée)
You can get more informations, or check-out other recipes which use it, for example: Salmon and leek fondue tart, Leek and Mimolette tart, Mexican tart, Potato and cheese pie, Black sesame flan, ... See them all 15
Smoked pork belly (or thick cut streaky bacon)
Like these other recipes: Soup Cornouaillaise, Express sauerkraut, Warm lentil salad, Boeuf (beef) bourguignon, ... See them all 4
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