A savory bread pudding featuring bacon, leeks, and cheese, perfect for using up stale bread. This strata can be made ahead of time, making it ideal for stress-free Christmas brunch.
1: Tear or cut the bread into 1-inch cubes.
2: Chop the bacon into bite-sized pieces and cook in a frying pan over medium-high heat until crispy.
3: Remove the bacon and nearly all of the bacon fat from the frying pan.
4: Add salted butter, leeks, and onions to the pan and cook until softened (about 8 minutes), seasoning with flaky sea salt and black pepper.
5: Whisk together eggs, cream, milk, Parmesan, Gruyère, Cheddar, cooked spinach, mustard, salt, and pepper.
6: Line a 10x15 baking dish with salted butter.
7: Layer 1/3 of the bread, followed by 1/3 of the leek and onions, 1/3 of the cheese, and 1/3 of the bacon. Repeat layering until ingredients are exhausted, reserving the final layer of cheese.
8: Pour the egg custard over the bread and top with the final layer of cheese.
9: Cover and place into the fridge overnight.
10: The next morning, preheat the oven to 175C/350F.
11: Bake for 50-60 minutes until golden and puffed.
12: Let rest for 5-10 minutes before serving.
