Croissant Bread Pudding

• Softened butter or vegetable oil, for greasing the pan
• 6 to 8 medium croissants (360 grams)
• 1 cup whole milk
• 1 cup heavy cream
• 1 lightly packed cup/200 grams light or dark brown sugar
• 3 large eggs, at room temperature
• 1 teaspoon vanilla extract
• 1/3 cup/40 grams chopped raw pecans
• 1/2 cup/113 grams unsalted butter (8 tablespoons)
• 1 lightly packed cup/200 grams light or dark brown sugar
• 1 large egg, at room temperature and lightly whisked
• 1/4 cup light or dark rum

Ice cream (optional), for serving

1. Prepare the pudding: Grease an 8-inch square or a 9-inch round baking pan with softened butter or oil. Cut the triangular ends off of the croissants, then cut the remaining parts into 4 to 6 large pieces. You should have about 7 cups. Place the croissant pieces in the pan, with the triangular ends on top, pointy edges up, and set aside.
2. In a large bowl, whisk together the milk, cream, sugar, eggs and vanilla until combined. Pour the mixture over the croissant pieces, then lightly press the croissant pieces down into the liquid. Some of them will spring back up and that’s OK. Sprinkle the pecans on top and cover and refrigerate for 1 to 2 hours, until the liquid is absorbed.
3. When ready to bake, position a rack in the center of the oven and heat to 350 degrees. Uncover the pan and bake until puffed and the custard is set, doesn’t appear wet, and only jiggles slightly when shaken, 35 to 45 minutes.
4. While the pudding is baking, make the rum sauce, if desired: Melt the butter and sugar in a small saucepan over medium-low heat, stirring occasionally. When the butter has melted and the sugar has dissolved, whisk vigorously with one hand while slowly drizzling in the whisked egg with the other hand. Cook on medium heat while whisking vigorously for 1 minute. Remove the saucepan from the heat, and stir in the rum. If there are any bits of cooked egg, strain the sauce through a fine sieve. The sauce can be stored in an airtight container in the refrigerator for up to one week.
5. Remove the pudding from the oven and let cool slightly before serving (as the pudding cools, it will deflate). If desired, serve with a generous pour of rum sauce or a scoop of ice cream. Store covered in the refrigerator for up to three days, and reheat individual servings in the microwave before serving.