-
1
Preheat an oven to 350 degrees F (175 degrees C).
-
2
Melt 1/2 cup butter in a large skillet; cook and stir the onion in the butter until caramelized, about 10 minutes.
-
3
Stir in the sugar and cook until the sugar completely melts, about 5 minutes.
-
4
Remove from heat and set aside to cool completely.
-
5
Mix together the flour, salt, and pepper in a shallow dish.
-
6
Whisk together the egg and water in a small bowl.
-
7
Dredge each chicken breast in the flour; shake off the excess flour and then dip the chicken in the egg and water mixture.
-
8
Heat the olive oil in a large skillet over medium-high heat; cook the chicken in the hot oil until completely browned, 5 to 7 minutes per side.
-
9
Place 2 of the chicken breast halves in the bottom of a baking dish.
-
10
Top each with about half the brie and half the caramelized onions.
-
11
Lie the remaining chicken breast halves atop the brie and onions.
-
12
Bake the chicken in the preheated oven until the cheese is melted and the chicken is no longer pink in the center, about 10 minutes.
-
13
While the chicken bakes, melt 2 tablespoons butter in a small skillet over medium heat.
-
14
Allow the butter to brown slightly before adding the vermouth; bring to a simmer and allow to cook until the liquid reduces by about half.
-
15
Season with the thyme, salt, and pepper.
-
16
Stir the arrowroot into the mixture to thicken.
-
17
Serve the sauce over the chicken.
