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Onion Gratin

  • Author: Tessa
  • Total Time: 1 hour 50 mins
  • Yield: 6 entree servings 1x


As I mentioned, I didn’t hate this gratin, but I didn’t love it. How’s that for convincing? In the spirit of my cook through commitment, I’m still sharing the recipe, but it will likely be updated just as soon as I return to it for a firmer version with more eggs and less liquid.


  • 2 T olive oil
  • 3 lbs. yellow onions, sliced 1/16 to 1/8 inch thick (about 8 medium)
  • 1 bay leaf
  • 1/2 t dried thyme
  • Sea salt
  • Ground black pepper
  • 1 C dry white wine (I used chardonnay)
  • 2 large eggs
  • 3 T flour
  • 1 1/2 C vegetable stock or milk, warmed (microwave or stovetop)
  • 2/3 C grated Gruyére
  • 1 t butter (for pan)
  • 3/4 C fresh bread crumbs


  1. In your largest skillet, heat oil over medium. Add onions, bay leaf, thyme, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Using tongs throughout, toss to coat. Reduce heat to medium low and cook onions about 40 minutes, until very soft but not browned. They should sizzle gently the entire time. Add wine, raise heat so liquid simmers, and cook about 15 more minutes until wine has reduced completely and the pan looks almost dry. Remove bay leaf.
  2. Preheat oven to 375 degrees (F).
  3. In a large bowl, whisk together eggs, flour, and another 1/2 and 1/4 teaspoon salt and pepper, respectively. While whisking quickly (so eggs don’t solidify), pour in warm stock. Add onions and cheese and stir to combine. Butter a 2 quart gratin or baking dish, then add the onion mixture. Top with a layer of bread crumbs. Bake 25 to 30 minutes, until bubbly and starting to brown. If bread crumbs are slow to brown but the dish is cooked, heat under the broiler for a few minutes, watching carefully to avoid burning. Let stand 5 minutes before cutting and serving.


Much of the prep time is relatively inactive, waiting for the onions to cook. Despite the prep time stated, this is one of the easiest gratins I’ve made yet.

Assemble the gratin ahead of time, waiting to add the bread crumbs until just before baking. If baking directly from the refrigerator, you may need to extend the cook time.

As suggested in the blog post, try more eggs for more solid pieces of gratin. My recommendation (untested) would be to add two egg, and reduce the stock or milk to 1 1/4 cup.

Adapted from Deborah Madison’s The New Vegetarian Cooking for Everyone.

  • Prep Time: 1 hour 20 mins
  • Cook Time: 30 mins
  • Category: Entree
  • Cuisine: Vegetarian