After purging them of blood, I might soak them in a flavorful liquid like stock, milk scented with nutmeg, or water with salt and a splash of acid like vinegar or citrus. This is where you can begin to layer flavors, and it's a great technique for lots of offal and organ meats-not just brains.

3. POACHING 

 
Poached brains
brains, after poaching with lemon and bay, are cooled in their liquid to help imbue flavor.

Once the brains are soaked, you could cook them fresh, but at least to start, especially if you're serving them to others, I recommend par cooking them to set their shape, making them easier to hide in things, and add layers of flavor. Next, the brains are poached in liquid, in my world this is typically with water, salt, bay leaf and lemon peel, although milk or a dairy mixture can be good too.  After the brains are cooked, about 20 minutes or so, they're cooled in their liquid, then refrigerated. 



poached, chilled brains 
Poached, chilled brains. They'll shrink to about half of their original size.

4. COOKING (REHEATING) 

After poaching and chilling comes the fun part: cooking, or reheating as the case may be. After cooking, brains will be firm, which makes them easy to handle and cut into attractive, evenly sized pieces. As they're heated, the brains will relax, getting delicate and creamy, a bit like fatty, semi-soft cheese.