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The appetizer, Regional

Hot baked oysters with leek gratin

Hot baked oysters are fresh oysters topped with a creamy leek fondue and gruyere, then broiled, serving 6 as a starter. They take about 35 minutes of active work, the leek fondue can be made the morning of, and the rest comes together right before guests arrive. Difficulty is moderate, about €3.80 per person, and success depends on a very hot broiler and a short cooking time so the oyster stays warm and tender.

Warm oysters topped with a creamy leek fondue and gratinéed, a surprise for anyone who hesitates to eat them raw.

Hot baked oysters with leek gratin
For
6 people
Work
35 min
Total time
50 min
Prep
Prepared the same day
Difficulty
Medium
Cost per person
€3.80
Calories per person
120 kcalcalculated by Kiloach, your weight coach

Under the golden gruyere, the oyster stays warm and plump, just barely cooked, while the creamy leek fondue softens its briny edge. It's a twist on the classic raw oyster that works well for guests who hesitate in front of a seafood platter. The rock salt that holds the shells steady on the platter is part of the fun, these are eaten standing up, by hand or with a small spoon.

This is a cold season recipe, built for a fall or winter cocktail party, a holiday gathering, or a dinner with friends where you want to make an impression without a complicated dish. It pairs naturally with a menu that stays rooted in hearty, rustic flavors, like roast poultry or a braise, and it disappears in a few bites before everyone sits down to eat.

The schedule

What happens when, so you can be with your guests instead of in the kitchen.

  1. The day before Nothing to do
  2. The same day 1 step, 15 min
  3. Before the guests arrive 4 steps, 19 min
  4. When it's time to serve 1 step

Make the leek fondue in the morning and keep it in the fridge. Right before guests arrive, shuck the oysters, set them on the rock salt, top with the fondue and gruyere, then broil them at the last moment. Serve immediately, the time between the broiler and the table needs to stay very short.

The ingredients

6 people

Fish counter

  • Oysters, size 3 18

Fruits and vegetables

  • Leeks 2

Dairy

  • Butter 30 g
  • Heavy cream 15 cl
  • Grated gruyere 50 g

Pantry

  • Rock saltoften in the pantry 1 kg
  • Pepperoften in the pantry 1 pinch

Allergens Mollusks, Lactose

The recipe, moment by moment

The same dayDuring the day, whenever you get a moment.

  1. Thinly slice the white part of the leeks and let them soften gently in the butter, then add the cream and let it reduce. 15 min

    Cook over low heat with the lid on at first, the leeks stay soft without browning.

Before the guests arriveThe last hour, right before the doorbell rings.

  1. Open the oysters with an oyster knife, keeping their liquid, and detach them from the shell. 15 min

    Wrap your hand in a kitchen towel and slide the knife in at the hinge, never force it.

  2. Set the oysters on a bed of rock salt in a dish and season with pepper.

    The rock salt keeps them level on the tray, so no liquid spills out.

  3. Top each oyster with a spoonful of leek fondue and sprinkle with gruyere.

    Don't overfill, the cream would spill over once it heats up.

  4. Broil under a very hot oven grill for a few minutes until the top turns golden. 4 min

    No more than 4 minutes, the oyster should just warm through, not cook.

When it's time to serveThe final touches, right in front of your guests.

  1. Serve right away on the platter, setting the rock salt on a bed of napkins.

    Set out a teaspoon for each guest, the shells are very hot.

Our tips to get it right

  • Pick medium oysters, plump but not oversized, they hold up better under the broiler without turning rubbery.
  • Taste the leek fondue before topping the oysters, it should be thick and creamy, not runny, or it will pool on the rock salt.
  • Use two sheet pans if your oven is small, broiling in two batches at very high heat works better than crowding the oysters and losing the broiler's heat.

The variations

  • Swap the gruyere for grated comte, it has a fruitier flavor and gratins just as well.
  • Stir a pinch of curry powder or saffron into the leek fondue for a more fragrant version.
  • For a faster version, make the leek fondue the day before and just shuck the oysters and broil them the day of.

What to serve it with

  • A glass of chilled Muscadet
  • Lightly buttered rye bread
  • A simple mâche salad as the next course

Storage

The leek fondue keeps for 2 days in the fridge in a sealed container. Baked oysters do not keep once cooked, they need to be eaten within a minute of coming out of the oven, and they cannot be frozen.

Questions about this recipe

Can the fishmonger shuck the oysters in advance?

They can, but the oysters lose some of their seawater and sit less securely on the rock salt. It's better to shuck them yourself right before cooking, keeping their liquid for extra tenderness.

How do you check an oyster is fresh before opening it?

The shell should stay tightly closed and feel heavy for its size. If it's slightly open and doesn't close when tapped, it's best to set it aside.

Can this recipe be scaled up for more than 6 guests?

Yes, just multiply the ingredients keeping the same amount of fondue per oyster. Plan on using several trays so the shells can broil without crowding.

Do these oysters need a separate sauce on the side?

No, the leek fondue already coats the oyster. A lemon wedge on the platter is enough for anyone who wants a bit of acidity.

Can hot baked oysters with a creamy leek gratin be made ahead?

Yes, during the day. The recipe needs 35 min of work in total, split up like this, the same day, 1 step, before the guests arrive, 4 steps, when it's time to serve, 1 step.

How long does it take to make hot baked oysters with a creamy leek gratin?

Allow 50 min in total, including resting and cooking time, of which 35 min is actual work. The recipe is rated "medium".

How many calories are in hot baked oysters with a creamy leek gratin?

About 120 kcal per person, for a recipe meant for 6 people. The calories are calculated by Kiloach, your kilo coach, the app that partners with Mon Chou.

How much does hot baked oysters with a creamy leek gratin cost?

About €3.80 per person, that's €22.80 for 6 people, based on average supermarket prices.

What allergens does this recipe contain?

This recipe contains mollusks, lactose. Remember to ask your guests about their allergies before putting your menu together.

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