Brioche egg sandwich on a plate.

Before heading out of town last weekend, I made a pan of Joanne Chang’s baked eggs.

If you are unfamiliar, Joanne Chang is the founder of Flour, a bakery and cafe in Boston (now with 9 locations), which serves a beloved egg sandwich. Unlike traditional egg sandwiches, which typically feature fried or scrambled eggs, Joanne’s calls for a pre-baked egg, made from a mixture of beaten eggs and half-and-half, baked at 300ºF in a covered pan set in a water bath.

The combination of the low temperature, the water bath, and the half-and-half creates an egg with a custardy, souffle-like texture, which reheats beautifully. And this is just what Joanne needed: without space to cook eggs to order at the bakery, the pre-baked egg allowed her to include an egg sandwich on her menu.

At Flour, the egg gets reheated to order with a slice of cheddar on top, and it’s served on a focaccia roll spread with dijonnaise, a mixture of mayonnaise and mustard, along with a slow-cooked tomato and bacon (if you wish).

It’s a spectacular combination and not only is it easy to make at home, it’s so nice to make at home. Why? Because with a stash of these egg squares on hand, a quick meal can materialize in no time.

As many of you know, I’m not much of a meal prepper. I make salad dressings in large batches and sauces ahead of time, but I have never been disciplined enough to spend weekends making meals for the week ahead.

But this I can do. Over the years, I’ve made Joanne’s recipe many times, but I find myself making it most often during particularly frazzled times: when we renovated our kitchen, for example, or throughout hockey season or, as in this past week, in an effort to lighten the load at home while I’m away.

Another bonus of the pre-baked egg? Egg sandwiches for a crowd. Place the egg squares on a sheet pan, each with a slice of cheese on top, and heat in the oven with the bun of choice — I like brioche buns — alongside. When the cheese is melty and the buns are toasty, remove, assemble, and serve.

Flour Bakery’s Egg Sandwiches, Step by Step

Gather your ingredients: eggs, salt, half-and-half.

A bowl of 9 eggs and 1 teaspoon salt.

Whisk together the eggs and salt first.

A bowl of beaten eggs.

Then add the half-and-half and whisk to combine.

A bowl of beaten eggs, 1/2 and 1/2, and salt.

Transfer to a buttered 8- or 9-inch baking dish.

Just-baked egg custard in a pan.

Set the pan in a 9×13-inch pan (or something similar) and …

Egg custard unbaked in a pan.

… pour boiling water into the large pan to reach 1/2- to 1-inch up the sides. Carefully transfer to a 300ºF oven, cover with a sheet pan, and bake for 25-35 minutes or…

A pan of eggs set inside another pan with 1/2-inch of water.

… until the custard is set.

Just baked egg custard.

Cut into 6 roughly equal rectangles.

Just-baked egg custard.

To make the egg sandwiches, place a slice of cheese over an egg rectangle on an oven-safe dish and transfer to the oven until…

A halved brioche bun on a sizzle pan aside an egg slice topped with cheese.

… the cheese is melted. I love a toasted brioche bun for this egg sandwich.

Toasted brioche aside melted cheese-topped egg slice.

Assemble your sandwich with garnishes of choice:

Brioche egg sandwich on a plate.

Note: When I’m really on my game, I’ll make the brioche rolls from scratch. I always, however, have a stash of store-bought brioche in the freezer, because they’re quite good and so nice to have on hand for these sandwiches.

Brioche egg sandwich on a plate.

I love the simplicity of greens, lightly dressed with oil and vinegar, on this sandwich.

Brioche egg sandwich on a plate.

As noted in the post, a slow-cooked tomato or bacon (or avocado or anything your heart desires) would all be great additions here.

Brioche egg sandwich on a plate.

Store the baked egg slices in an airtight vessel in the fridge for up to 1 week. It is so nice having a stash of these eggs on hand for quick meals.

Egg slices in a glass storage container.

Here they are on homemade buns with roasted red peppers and pea shoots.

Joanne Chang's breakfast sandwich.
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Joanne Chang's breakfast sandwich.

Joanne Chang’s Egg Sandwich

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Description

From Joanne Chang’s cookbook Flour, Too. 

Notes:

A few changes from the original recipe:

  • Shorter cooking time: I find 25-30 minutes (as opposed to 40 minutes) to be about right. Do rely on visual cues, however, as every oven is different. 
  • No pepper or thyme in the eggs (not because I don’t like them but because the recipe calls for adding them after 20 minutes of baking, which has always felt a little fussy). 
  • I cut the egg custard into 6 pieces as opposed to 4. 

Salt: I always use Diamond Crystal kosher salt. If you are using Morton’s kosher salt or fine sea salt use half the amount by volume (1/2 teaspoon) or the same amount by weight (5 grams). 

Ingredients

For the eggs:

  • 9 eggs
  • 1 teaspoon (5 g) kosher salt, see note
  • 3/4 cup half-and-half or heavy cream

For one egg sandwich (scale up as needed):

  • 1 slice cheese, I’ve been using Cheddar
  • 1 egg rectangle, from the baked egg portion of the recipe
  • 1 brioche roll, homemade or otherwise
  • butter or other sauce of choice
  • lettuce, optional
  • oil and vinegar, optional, for the greens
  • hot sauce, roasted red peppers, avocado, bacon, or any other additions you wish, for serving

Instructions

Make the Eggs:

  1. Preheat the oven to 300ºF. Butter an 8- or 9-inch square baking dish. Bring a pot of water to a boil — I use my electric tea kettle, which holds about 4 cups.
  2. In a large bowl, whisk together the eggs and salt. Add the half-and-half and whisk to combine. Transfer the eggs to the prepared pan. 
  3. Set the pan inside a 9×13-inch baking dish. Carefully pour the boiling water into the 9×13-inch baking dish. Carefully transfer the pan to the oven. Set a sheet pan on top of the pan to cover. Cook for 25-35 minutes (or potentially longer), but start checking after 25 minutes. To check for doneness, remove the sheet pan, and gently touch the egg custard — it should feel set. If it is not set, recover the pan and set the timer for 5 minutes more. My eggs consistently cook in 25 to 30 minutes. 
  4. Carefully remove the egg custard from the water bath and set it on a cooling rack. Let rest for 10 minutes before cutting. Cut into 6 rectangles. Proceed with the recipe or transfer the rectangles to a storage vessel and store in the fridge for up to 1 week. 

To Make the Sandwich:

  1. Place the egg on an oven-safe dish — I like these sizzle pans — and lay a slice of cheese on top. Transfer to a 350ºF oven for 4 to 5 minutes or until the cheese has melted. I do this in my toaster oven and toast the brioche bun alongside — do keep an eye on the brioche bun, however, as it tends to toast before the egg/cheese piece is ready. Also, depending on if your eggs were refrigerated or not, this will take more or less time. If my egg pieces have been refrigerated, I’ll heat them without cheese in the toaster oven for 3 to 4 minutes, then I’ll top with a slice of cheese and heat for another 1 minute or so.  (Alternatively: heat the egg-cheese combo in the microwave for 60 to 90 seconds.)
  2. Toast the brioche: you can do this in a toaster or an oven depending on what you prefer. 
  3. Spread butter or sauce of choice over the toasted brioche. Top with an egg-and-cheese slice. Top with hot sauce, if using, and any other additions: greens (lightly dressed with oil and vinegar), roasted red peppers, avocado, etc. 
  • Prep Time: 10 minutes
  • Cook Time: 30 minutes
  • Category: Breakfast
  • Method: Oven
  • Cuisine: American