In a small bowl, whisk together all of the ingredients. Set aside.
With your hands or a hamburger press, form the meat into 4 patties.
In a large non-stick skillet over medium-high heat, brown the hamburger buns in 1 tbsp of the butter. Keep warm.
In the same skillet over medium-high heat, brown the patties in the remaining butter for 4 minutes on each side or until cooked through. Lightly season with salt and pepper. Top each patty with a piece of the processed cheese, a slice of cheddar and a sprinkling of mozzarella. Cover the skillet and remove from the heat to let the cheese melt while the skillet is still hot.
Spread the inside of the buns with the sauce. Cover the bottom half of the buns with half of the broccoli and top with the patties and remaining broccoli, then close the buns.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.