This Green Tomato Gratin features tart tender green tomatoes surrounded by a cheesy mornay sauce, topped with crisp herbed breadcrumbs. It makes a for a delicious side, but works equally well for brunch, topped with poached eggs and served with toast.

Tart tender green tomatoes are surrounded by a cheesy mornay sauce bubbling up from below in this Green Tomato Gratin. With a crisp panko and herb topping, this decadent side is addictively good.

With the weather up in the 80’s in Tokyo this week, it really feels like we’ve blown through spring and headed straight into summer. To reassure my senses that the withering heat of summer is still a few weeks off, I picked up some springy green tomatoes at the local vegetable stand. Whether it’s peaches, papaya or mangoes, I have a penchant for unripe fruit, and green tomatoes are no exception.

For me, unripe fruit isn’t just a consequence of corporate farming, it’s a unique ingredient with its own texture and unique flavor profile that can be delicious when properly prepared. It’s also a fun challenge to come up with with new ways of using a familiar ingredient. I first made this green tomato gratin years ago when I still lived in New York, and and it’s since become a favorite when these firm verdant jewels of spring are available in markets.

Green tomatoes for making a gratin.

The rich mornay sauce provides the perfect contrast to the tart fragrant green tomatoes. When baked in the oven, the two meld together creating a well balanced side with a crisp, flavorful topping that goes beautifully with grilled meat. It also makes for a delightfully decadent breakfast when served with some poached eggs and toast.

A rich, cheese green tomato gratin with a crispy herb and panko topping.

Green Tomato GratinTart tender green tomatoes surrounded by a cheesy mornay sauce, topped with crisp herbed panko.


  • CourseAppetizer
  • CuisineAmerican
  • Yield2 servings
  • Cooking Time45 minutes
  • Preperation Time5 minutes
  • Total Time50 minutes


300 grams
green tomatoes (sliced 1/4" thick)
breadcrumb topping
1/2 cup
1/4 teaspoon
onion powder
1/4 teaspoon
celery seeds
1/8 teaspoon
ground black pepper
1 tablespoon
olive oil
mornay sauce
1 tablespoon
cultured unsalted butter
2 teaspoons
all-purpose flour
1/2 cup
heavy cream
1/4 teaspoon
50 grams
Comté cheese


  1. Put the oven rack in the middle position and preheat to 375 degrees F.
  2. The panko and herb topping for the green tomato gratin
    To make the topping, mix the panko, onion powder, celery seeds, salt and pepper until everything is evenly distributed and then drizzle on the olive oil and stir to combine.
  3. Start the mornay sauce by making a flour and butter roux.
    To make the mornay sauce, put the butter and flour in a small saucepan and cook over medium heat until the mixture is bubbly, but do not let the flour brown.
  4. A rich bechamel before the cheese is added.
    Turn the heat down and then whisk in the cream until the mixture is free of lumps and it starts to thicken.
  5. Comte cheese added to the mornay sauce.
    Once the sauce thickens, add the salt and stir in the cheese a little bit at a time until it is all incorporated. The mornay sauce will be very thick, but this is okay since the the tomatoes will release a lot of water.
  6. The green tomatoes are layered with the cheesy mornay sauce.
    Arrange the sliced green tomatoes and mornay sauce in layers in an oven safe dish and then spread any remaining sauce on top of the green tomatoes.
  7. The panko and herb topping goes on top of the Green Tomato Gratin.
    Sprinkle the panko topping evenly over the top of the tomatoes and then place the dish in the oven. Bake for 30-35 minutes or until the sauce is bubbling, the tomatoes are tender, and the breadcrumbs are golden brown.