Apple-Gruyère French Toast

Ingredients

• Two 1 3/4-inch-thick slices challah bread from middle of loaf
• 2 ounces grated Gruyère cheese
• 1/4 small red onion, very thinly sliced
• 2 large eggs, lightly beaten
• 3/4 cup whole milk
• 1/4 teaspoon kosher salt
• 1/4 teaspoon ground black pepper
• 2 tablespoons extra virgin olive oil
• 1 small apple, cored, quartered and very thinly sliced

Directions

1. Set 1 slice of bread on your counter with the lower crust facing you. Slide your knife into that lower crust, keeping it level with the counter, and open up a pocket without cutting through the top, so the bread stays connected. Tuck half the cheese and onion slices inside, gently but firmly. Do the same thing with the other slice.
2. In a bowl, beat the eggs with the milk, salt, and pepper. Transfer the custard to a shallow, wide dish. Nestle the filled bread into the custard, flip it once midway through, and let it soak until it has taken in most of the liquid, about 5 minutes.
3. Warm the oil over medium heat in a large skillet. Lay in half of the apple slices, keeping them in one layer, and give them 1 minute. Set the bread on top so it covers the apples. Scatter the rest of the apple slices over the bread, then cook for 1 minute longer.
4. Turn the heat down to medium low, or low if your skillet is cast-iron or your burner runs hot, put on a cover, and cook for 5 minutes. If your skillet does not have a lid, shape a little cover from aluminum foil. Check the underside midway through so the bread is not getting too dark; if it is, lower the flame or go straight to uncovering it, depending on how browned it already looks. Remove the cover, bring the heat back to medium, and cook until the bottoms are golden, about 2 minutes. Carefully flip the bread with the apples and cook until the bread is golden and the cheese has melted, 3 to 5 minutes.