Preheat barbeque to medium heat (350°F/175°C).
In a small bowl mix cinnamon and sugar. Place the mixture on a small plate.
Brush both sides of each donut with melted butter.
Dip each side of the donut in the cinnamon sugar mixture.
Place each donut on the grill and top with the foil-covered bricks to weigh them down.
Cook for 2 minutes per side or until the sugar is caramelized and donuts is crispy and toasted.
Remove from grill and serve with coffee, a dollop of crème fraiche or ice cream.