Creamy Roasted Asparagus Soup

Bahan-bahan (4 porsi)

• 2 lbs asparagus
• 1 large yellow onion, peeled and halved
• 4 cloves garlic, not peeled and left whole
• 2 Tbsp . olive oil
• 5 cups chicken broth
• 1/2 tsp . dried thyme
• 1/2 cup half and half (or heavy cream)
• 1 Tbsp . dry vermouth (or dry white wine)
• squeeze of fresh lemon juice
• salt and freshly ground black pepper