Preheat your oven to 300 °F (150 °C).

Heat plenty of water to 160 °F (70 °C). It's best to use a thermometer to measure the water temperature. Pour the hot water into a large casserole or any other large ovenproof dish so that it is about 2 inches deep. Place inside the oven.

Heat up the milk to about 140 °F (60 °C) on the stovetop or in your microwave. Crack the eggs into a small bowl and whisk them lightly until smooth. Pour in the milk and continue whisking lightly. Stop once the mixture is smooth. Don't whisk too vigorously as you don't want to introduce air bubbles into the custard. Season the egg-milk to taste with nutmeg and salt.

Grease the surface of a small casserole or any other ovenproof dish that will fit inside your water bath with butter to make it nonstick. Strain the egg-milk through a fine-mesh sieve into your greased casserole or ovenproof dish. Remove any remaining air bubbles on the surface with a spoon and cover tightly with aluminum foil. Place in the water bath inside your preheated oven. Let the custard slowly coagulate which usually takes between 45-60 minutes. Take the set custard out of the oven. It's best to let it cool down before slicing. Once chilled, invert the custard onto a cutting board. Slice the custard into the shape of your preference or use cookie cutters to make it look fancy.

To serve, ladle some hot broth on top of your custard and enjoy as a soup.