2 large sweet onions, peeled and sliced into quarters
2 shallots, peeled and sliced in half
1 head of garlic
1 tablespoon olive oil
1 teaspoon salt
1/2 teaspoon white pepper
4 cups good-quality chicken stock (we like Kitchen Basics brand)
1/4 cup dry sherry
1/3 cup heavy cream
Leaves from 1 sprig fresh thyme or tarragon
Preheat oven to 375 F. Place onions and shallots on a baking sheet and drizzle with most of the olive oil. Season with salt and toss to coat. Slice the top 1/4" off of the garlic bulb, drizzle with remaining oil and wrap in aluminum foil. Roast onions, shallots and garlic for 35-40 minutes, until onions are softened and caramelized. Remove from oven and let rest until cool enough to handle.
Once cool enough to work with, extract the roasted garlic cloves from the bulb by squeezing the bulb as firmly as you can onto a work surface.
Working in batches, add half of the roasted onions, shallots and garlic to a blender along with half of the stock. Blend until very smooth; you can strain the mixture to remove any larger particles if you like but it's not necessary.
Add mixture to a stock pot and stir in cream, sherry, pepper and herb leaves. Bring to a simmer and cook for 10 minutes. Serve immediately.