Cup of Yum
1. In a small bowl, mix together the mayonnaise, grated garlic, and half of the thyme leaves. Set aside.
2. Add the olive oil to a large skillet over medium high heat. Add the onions and cook a few minutes or until wilted. Add the mushrooms and the remaining thyme. Stir together well, reduce the heat to medium, cover and cook until the onions are caramelized and the mushrooms and cooked through. Remove from pan and set aside.
3. Place the skillet back on medium high heat and add the bacon. Cook until crisp and brown. Remove the bacon and set aside.
4. Drain all but 3 tablespoons of bacon fat from the skillet. Add the chicken breasts and cook, turning occasionally, until done.
5. Preheat the oven to 350 degrees.

Assemble the sandwich:

Cup of Yum
1. Slice the boule through the center. Remove most of the soft interior of the bread leaving a thick wall around the outside edge.
2. Generously spread the cut sides of the bread with the mayonnaise mixture. Top with the bacon, thick slices of brie, sliced chicken breasts, and the caramelized onions and mushrooms. Place the top on the loaf and wrap in aluminum foil.
3. Place on center rack of oven and cook for 5-6 minutes or until the brie has begun to melt.
4. Remove from the oven and slice into wedges.