Sauté the Onion and Garlic:
In a large pot, heat the olive oil and butter over medium heat. Add the chopped onion and sauté for about 5 minutes, until softened.
Add the peeled garlic cloves and cook for an additional 2-3 minutes, stirring frequently to avoid burning.
Add the Broth and Herbs:
Pour in the broth and add the thyme sprigs and bay leaves. Bring the soup to a boil, then reduce the heat and let it simmer gently for 30 minutes, allowing the garlic to soften and release its flavor.
Remove Herbs and Season:
After 30 minutes, remove the thyme sprigs and bay leaves from the soup. Season with salt and pepper to taste.
Temper the Egg Yolks:
In a small bowl, whisk together the egg yolks and Parmesan cheese. Slowly whisk a ladle of hot soup into the egg mixture to temper the eggs and prevent curdling.
Gradually whisk this mixture back into the soup pot.
Thicken the Soup:
Simmer the soup for another 5 minutes, stirring continuously until the soup thickens slightly.
Serve:
Ladle the hot soup into bowls and serve with crusty bread on the side. Optionally, garnish with fresh parsley for added flavor and color.
This velvety, garlic-rich soup is perfect for warming up on chilly days, pairing wonderfully with crusty bread for dipping.
Prep Time: 10 minutes | Cook Time: 35 minutes | Total Time: 45 minutes