Here's my recipe. It is basically something I stole off epicurious but with one addition of my own!!
(Health warning: this is not an everyday soup and it is not good for your health! This is the kind of thing you serve in tiny dishes with tiny spoons to posh guests for whom you cannot make regulation beans on toast).
This recipe uses an amazing cheat ingredient I have found, which is Colgin liquid smoke. I now use this in a whole load of dishes, from chilli right through to the aforementioned regulation beans on toast 
Shove's cheatin' smokin' garlic soup
26 garlic cloves (unpeeled)
2 tablespoons olive oil
1 tablespoon butter
375g sliced onions
1 1/2 teaspoons chopped fresh thyme
18 garlic cloves, peeled (yes, these are a separate lot from the first 26)
700 ml Marigold bouillon (less if you want a really thick soup)
125ml cream
Parmesan cheese (about 2 ounces)
4 lemon wedges
Amazing cheat ingredient: 2 tablespoons of Colgin liquid smoke (you can buy it from the website Souschef)
Preheat oven to 180 C. Place 26 garlic cloves in small glass baking dish. Add 2 tablespoons olive oil and sprinkle with salt and pepper; toss to coat. Cover with foil and bake until garlic is golden brown and tender, about 45 minutes. Cool. Squeeze garlic between fingertips to release cloves. Transfer cloves to small bowl.
Melt butter in heavy large saucepan over medium-high heat. Add onions and thyme and cook until onions are translucent, about 6 minutes. Add roasted garlic and 18 raw garlic cloves and cook 3 minutes. Add stock; cover and simmer until garlic is very tender, about 20 minutes.
Purée soup in blender until really smooth. Return soup to saucepan; add cream and bring to simmer. Season with salt and pepper. Add about a tablespoon or two (more to taste) of liquid smoke right at the end.
Grate some cheese over in the bowl and squeeze some lemon over it.