Clean the mussels by scrubbing the shells thoroughly. If using New Zealand mussels that are already shelled, you can skip this step.

Cut the bacon into pieces. Cook the bacon over medium heat until crispy, or you can use a convection oven.

Heat a pan over medium heat and add butter. Sauté the garlic.

When the garlic turns golden, add the diced onion and sauté.

Once the onion is cooked, add the cornstarch and stir. Add a little fish stock to prevent burning.

Add milk or heavy cream, followed by the fish stock.

When everything starts to boil, add the mussels and mushrooms. Cover and cook over medium heat for 6 minutes.

After 6 minutes, add parsley and season with salt and black pepper. Taste to ensure a rich, slightly salty flavor similar to carbonara.