Ham & Cheese Croissant Bread Pudding

 

4 T. (5 5 g) unsalted butter, plus more for greasing the pan

2 yellow onions, diced

2 T. fresh thyme leaves, plus more for garnish

2 T. Dijon mustard

Kosher salt and freshly cracked black pepper

8 large eggs

2 C. (480 ml) half-and-half

2 C. (220 g) grated Gruyere cheese

6 ounces (170 g) smoked ham, cut into 1-inch (2.5 cm) pieces

1 pound (455 g) croissants, ripped into 2-inch (5 cm) pieces (about 10 cups)

1/2 C. (50 g) grated Parmesan cheese

Flaky salt

 

Generously butter a 9 by 13-inch (23 by 3 3 cm) baking dish; set aside. In a skillet over medium heat, melt the butter. Add the onions, reduce the heat to low, and cook until the onions are very soft and beginning to caramelize, about 10 minutes. Add the thyme, mustard, and salt and pepper and continue to cook, stirring occasionally, for 5 minutes more. Remove from the heat and let cool slightly. In a large bowl, whisk the eggs and half-and-half until combined. Season with salt and pepper. Add the onion mixture, Gruyere, and ham, then add the croissant pieces and stir to coat them. Transfer the bread pudding mixture to the prepared dish, pressing it gently into the dish. Top with the Parmesan and cover with aluminum foil. Transfer to the refrigerator to chill for at least 1 hour or up to overnight. When ready to prepare, preheat the oven to 35O°F (175 °C). Bake the covered bread pudding on the center oven rack for 30 minutes. Then uncover and continue to bake until the Parmesan has melted and turned golden, about 20 minutes longer. Allow to cool for 10 minutes, then serve warm with freshly cracked black pepper, flaky salt, and tons of fresh thyme.