In a large skillet, melt the butter over medium heat and sauté the onions until transparent, 5 to 8 minutes. Add half the broccoli and the roasted garlic and sauté until soft, 8 to 10 minutes. Add the stock and bring to a boil. Reduce the heat and simmer gently for 10 minutes.

Add the remaining broccoli and the cream. Bring to a boil and cook until the newly added broccoli is tender, about 10 minutes. Puree in a blender and strain through a coarse strainer. Season with salt and pepper and keep hot.

For the shrimp and mushrooms:

Preheat the oven to 200°F. In a large skillet, heat the olive oil over medium-high heat until shimmering. Add the mushroom caps and sauté until soft, about 6 minutes. Remove from the skillet. Add the shrimp to the skillet and sauté until medium-rare, 1 to 2 minutes each side. Keep warm in the oven.

To serve:

Put the mushrooms and shrimp in 8 warm bowls and ladle the soup over.

Variations:

Instead of sautéing the shrimp and mushrooms, grill the mushroom caps until golden and the shrimp until medium rare, 1 to 2 minutes each side.

For chicken stock substitute half chicken, half lobster stock.