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Croque Monsieur

How to Make the Ultimate Pastrami Croque Monsieur - The Secrets of French Cuisine

The croque monsieur, the holy grail of all grilled cheese sandwiches, is the ultimate comfort food. Here's the definitive recipe for how to make yours using pastrami and Gruyère cheese.

18 November, 2021
Average: 4.6 (10 votes)

serves for



Mornay sauce
1 ¼ cup
2 tbsp
All purpose flour
2 tbsp
¼ tsp
1 pc chopped
1 pc chopped
Lemon zest
¼ pc
2 sprigs
Gruyère Cheese
4 oz grated
Salt and pepper
to taste
Pickled shallots
Rice Vinegar
½ cup
½ cup
Caster sugar
½ cup
Bay leaf
1 bay leaf
Coriander seeds
1 tsp
Star anise
1 pc
¼ pc
Duck fat fries
Floury potatoes
Duck Fat
1 lb
Canola oil
½ lb
Bay leaf
Croque Monsieur
8 slices sourdough
Gruyère Cheese
8 slices
Mornay Sauce
16 tbsp
4 tbsp pickled shallots
16 oz medium pastrami sliced
4 oz (soft)
4 tbsp

Step 01

Mornay Sauce_Step one

For the mornay sauce

In a saucepan, place the milk with the onion, shallots, nutmeg, and thyme.

Step 02

Mornay Sauce_Step two

Bring it to a simmer and let it steep for 10-15 min.

Step 03

Mornay Sauce_Step three

Meanwhile, make a roux by whisking the flour and butter in a small saucepan for 2-3 min or until the flour is cooked off.


Step 04

Mornay Sauce_step four

Strain the milk and discard the aromatics.

Step 05

Mornay Sauce_Step five

Slowly whisk the milk into the roux. Cook the béchamel until obtaining the desired consistency.

Step 06

Mornay Sauce_step 6

Season with salt and pepper. Add the cheese and lemon zest.

Step 07

Mornay Sauce_Step seven

Place the mornay in a container, place a piece of plastic wrap over the sauce to prevent from creating a skin and set aside.

Step 08

Pickled Shallots_Step one

For the pickled shallots

Place all the ingredients except the shallots in a saucepan and bring it to a simmer.  

Step 09

Pickled Shallots_Step two

Let it steep for 5 minutes

Step 10

Pickled Shallots_Step three

Slice the shallots thin and split the rings.

Step 11

Pickled Shallots_step four

Pour over the pickling liquid, cool down and reserve.

Step 12

Duck fat fries_Step one

Duck fat fries

Peel and cut the potatoes to the desired size.

Step 13

Duck fat fries

Place the fries in a large pot with salted cold water. Bring it to a boil then strain. Place them in a tray over a towel or absorbing paper and let it cool down at room temperature.

Step 14

Duck Fat Fries

Bring the duck fat and canola oil to 250F and cook the potatoes for 4 minutes. Take them off and place on top of the same tray with a towel. Cool down at room temperature.

Step 15

Duck Fat Fries

Bring the duck fat oil to 350F and cook the fries until golden brown and crispy, about 3-4 min.

Step 16

Duck Fat Fries

Place in a bowl with a paper towel and season right away.


Step 17

Croque Monsieur_Step one

Croque monsieur

Start by buttering the inside of the bread, place the pastrami on one side and top up with some pickled shallots and Gruyère.

Step 18

Croque Monsieur_Step two

Spread mornay on the other side of the bread and on top of the cheese. Close the sandwiches and spread mayo on the outside layers of the bread.

Step 19

Croque Monsieur

In a frying pan, place the butter until foaming and add the sandwiches. Cook until golden brown and flip them on the other side.

Step 20

Croque Monsieur

Place the pan in a 350F oven for 5 min.

Step 21

Croque Monsieur

Slice the sandwiches in half and serve with the duck fat fries.

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