Overnight Sharp Cheddar Bread Souffle

Using a serrated knife, slice the sourdough bread into evenly sized 2.5cm cubes.

Use a box grater to shred the sharp cheddar and finely grate the parmesan cheese. Toss them together in a small bowl.

Generously coat the inside of your souffle dish or baking dish with the softened butter. Arrange half of the bread cubes in the bottom, then sprinkle with half of the cheese mixture. Layer the remaining bread on top, followed by the remaining cheese.

In a large mixing bowl, combine the eggs, whole milk, heavy cream, dijon mustard, garlic powder, kosher salt, and black pepper. Whisk vigorously until the eggs are completely broken down, the mustard is fully incorporated, and the mixture is uniformly yellow and lightly frothy.

Slowly pour the egg custard evenly over the layered bread and cheese. Press down firmly on the top layer of bread with your hands or a spatula to ensure all the pieces are soaked in the liquid.

Cover the dish tightly with plastic wrap and transfer it to the refrigerator. Let it rest overnight for at least 8 hours so the bread fully hydrates and the starches begin to break down, which creates the souffle-like texture.

The next day, remove the dish from the refrigerator to take the chill off while the oven heats. Preheat your oven to 175 degrees Celsius or 350 degrees Fahrenheit.

Remove the plastic wrap and bake the dish uncovered on the middle rack for 50 to 60 minutes. The dish is done when it has puffed up significantly, the top is deeply golden brown, and a thermometer inserted into the center reads 74 degrees Celsius or 165 degrees Fahrenheit.

Remove the souffle from the oven and allow it to rest for 10 minutes before serving. Note that it will naturally deflate slightly as it cools, which is expected.