In a large bowl, combine strawberries, sugar, and liqueur. Let stand 1 hour, stirring occasionally.
Set up grill for direct cooking over medium heat. Oil grate when ready to start cooking.
In a shallow bowl, whisk together eggs, milk, liqueur, and sugar. Coat each slice of bread on both sides with egg mixture. Place coated bread slices on hot oiled grill. Cook for 3 to 4 minutes per side.
To serve, place 1 piece of French toast on plate. Top with strawberries and whipped topping. Add another slice of French toast and repeat.
INDOOR: Prepare bread slices as directed. Melt 2 to 3 tablespoons of butter on a hot griddle (over medium-high heat). Cook prepared bread slices until golden brown on both sides. Serve as directed.