Potato Tomato Gratin · Thyme for Cooking



The theme for Monday posts in September is Vegetable Gratins.

Actually, that is going to be the theme for October, also.

I make a lot of vegetable gratins

According to the Powers That Be that run the internet. “A gratin is a dish that is topped with cheese, or bread crumbs mixed with bits of butter, then heated in the oven or under the grill until brown and crisp. The terms au gratin or gratinée refer to any dish prepared in such a manner.”

Those PTB are obviously British as we Americans would say ‘broiler’ rather than ‘grill’ but you get the idea.

I rarely do the butter and bread crumbs bit, and I don’t always put the cheese on top. Sometimes it gets mixed in.

The important things is, my gratins are always easy. Top them however you like.

Potato & Tomato Gratin


Potato Tomato Gratin

Potato Tomato Gratin

Use a strong cheese for this – Munster or sharp Cheddar would be good.

  • Author: Kate
  • Prep Time: 15 minutes
  • Cook Time: 60 minutes
  • Total Time: 1 hour 15 minutes
  • Yield: 4 servings 1x
  • Category: Potatoes
  • Method: Oven
  • 4 medium potatoes, 20oz total (600gr), thinly sliced
  • 1 large onion or 2 smaller onions,  12oz total (350gr), thinly sliced
  • 23 tomatoes, 12 – 14oz total (350-425bg), thinly sliced
  • 2 cloves garlic, minced
  • 1 tbs olive oil
  • 3oz (90gr) strong cheese of choice, shredded
  • 1 tbs dried sage
  • 1/4 cup (2oz, 60ml) chicken broth
  • 1/4 cup (1oz, 30gr) grated Parmesan
  • Heat oil in a medium skillet over medium-high heat.
  • Add onions, garlic and sauté until tender and starting to brown, about 10 minutes.
  • Remove from heat and set aside.
  • In large baking dish lay 1/3rd of the potatoes.
  • Spread half of the sautéed onions over the potatoes.
  • Add a layer of tomatoes, touching but not overlapping.
  • Spread half of the shredded cheese on the tomatoes and sprinkle with half of the sage.
  • Repeat layers once.
  • Top with remaining 1/3 of the potatoes.
  • Pour the stock over all, sprinkle with Parmesan, cover with foil and bake at 425F (210C) for 40 minutes.
  • Remove foil, reduce heat to 400F (200C) and continue baking another 20 minutes.
  • Remove from oven, let rest 5 – 10 minutes, cut and serve.


Try to get 8 – 10 slices from each tomato. A serrated knife works well.
Or use a mandolin for all slicing.
I used an 8″ x 11″ (20 x 27.5cm) baking dish.
Use 10 – 12 fresh sage leaves for the dried.


  • Serving Size: 1/4 recipe
  • Calories: 320
  • Sugar: 6.7 g
  • Sodium: 321.8 mg
  • Fat: 12.5 g
  • Saturated Fat: 5.5 g
  • Trans Fat: 0.2 g
  • Carbohydrates: 42.2 g
  • Fiber: 7.1 g
  • Protein: 11.8 g
  • Cholesterol: 25 mg

Keywords: potato gratin, potatoes

Another summer veggie gratin: Potato & Summer Squash Gratin

That’s it!