In a medium size mixing bowl whisk together eggs, milk, cream, ¼ cup sugar, cinnamon, vanilla, salt and nutmeg until fully combined.
Pour about half onto a rimmed 12 x 18 inch sheet pan. Arrange bread slices on pan, pouring remaining evenly over top. Let sit for 15 minutes then, turn. Cover pan with plastic wrap and chill overnight. Turn one more time, if possible.
To bake: Preheat oven to 425°F. Once preheated, a clean 12 x 18 inch pan to oven with 2 Tbsp butter. Let heat for around 5 minutes or until butter melts. Lower oven temperature to 400°F.
Remove pan from oven and swirl butter to coat pan or brush with a pastry brush. (Be careful, the pan is hot) Uncover french toast, and sprinkle top sides of all with 1 Tbsp sugar.
Place bread sugar side down on hot pan. Repeat sprinkling top sides of all with remaining 1 Tbsp sugar. (You can use more sugar on each side, if needed)
Bake for 20 minutes, then flip. Add pats or cubes of the remaining 2 Tbsp butter to pan, placing randomly around bread slices. Bake for another 15 minutes or until puffed and golden. (Increase to broil at the end of baking, if desired to caramelize further.)
Serve immediately dusted with powdered sugar, maple syrup and fresh berries.