Cut the top 1/4 inch off of the garlic head. Top with 1 tablespoon butter and teaspoon of lemon juice. Wrap in foil and roasted for 45 - 50 minutes or until tender. Allow to cool. Use a fork to remove each clove and mash in a bowl. Set aside.
Heat olive oil in a skillet over medium heat. Once hot, cook mushrooms for 3 - 4 minutes or until browned. Add in kale and cook just until wilted, about 2 minutes.
Butter one side of each slice of bread. One the other side of the bread spread a thin layer of roasted garlic. Divide the cheese evenly among four slices of bread. Divide the sauteed kale and mushrooms and place on top of the cheese. Place the remaining four slices of bread on top butter side out. Grill 2 - 3 minutes on each side or until the bread is golden and the cheese is melted.