Preheat oven to 350F. Spray a 9 x 13 inch baking dish with olive oil spray.

In a large skillet, over medium heat add 1 teaspoon olive oil and garlic and cook 30 seconds. Add the broccoli, 1/4 teaspoon kosher salt, 1 tablespoon of water and cover.

Let the broccoli cook until tender crisp, 3 minutes. Transfer to the baking dish.

Pound the thicker end of the chicken breast to make it even on both sides. Brush mayo on the chicken and season with 1/2 teaspoon salt and black pepper, to taste.

Heat the skillet over medium heat, when hot spray with oil and cook the chicken until just about cooked through, about 5 minutes on each side.

Remove from heat and transfer chicken to a cutting board. When cooled, slice chicken into bite sized pieces.

Reduce the heat of the skillet to medium heat. Add the butter and remaining oil until melted and then add the shallots and cook until tender, 2 to 3 minutes.

Sprinkle the flour and cook, stirring about 1 minute. Whisk in broth, milk, 1/2 teaspoon salt and sherry and bring to a simmer about 1 1/2 minutes on low. Remove from heat and stir in half of the Swiss cheese.

Pour half of the sauce over the broccoli and mix to coat. Arrange the chicken on top and cover with remaining sauce.

Sprinkle the remaining Swiss cheese, grated Parmesan and top with breadcrumbs.

Spritz a little oil on top. Bake 30 minutes, until hot and golden.