Step 1

In a large skillet, soften the butter over medium heat. Add the shallots and garlic, and cook until translucent and aromatic.

Step 2

Cook the sliced mushrooms until they are tender and have released their moisture in a skillet. This should take between 8 and 10 minutes.

Step 3

Add the fresh thyme leaves and season to taste with salt and pepper. Permit the flavors to combine for one minute.

Step 4

Pour the heavy cream into the sauce and bring it to a simmer. Allow the cream to simmer for approximately 5 minutes, allowing it to reduce slightly.

Step 5

Stir in the grated Parmesan cheese until it dissolves completely, creating a sauce that is velvety and creamy.

Step 6

If necessary, modify the seasoning of the sauce. Remember that the flavors should be harmonious and well-balanced.

Step 7

Take the sauce off the heat and allow it to settle for a few minutes. It will become slightly thicker as it cools.