Cut each slice of the brioche bread diagonally creating 18 triangles. Butter one side of each piece and place butter side up in the 9x13 baking dish.
Filling:
In a medium bowl, whisk together half and half, eggs, vanilla cinnamon, and nutmeg. Pour evenly over the bread. Cover with plastic wrap.
Glaze:
In a small bowl whisk together all of the ingredients of the glaze. Pour glaze into a labeled quart-size freezer bag, remove as much air as possible and seal.
MAKE IT NOW
Place baking dish in refrigerator for at least 6 hours or overnight. Preheat oven to 350F (180C). Remove plastic wrap. Bake for 40 minutes or until a tested inserted in the center comes out clean. Remove from oven and let cool for 5 minutes. Drizzle glaze evenly over the top.
MAKE IT A FREEZER MEAL
Wrap the pan tightly with plastic wrap, pressing down gently to remove air. Place glaze bag on top of pan and cover both with foil. Label and place in freezer.
COOK FROM FROZEN
Preheat oven to 350F (180C). Remove foil, glaze packet, and plastic wrap. Place frozen pan directly into oven and bake for 55-60 minutes, until a tester inserted into the center comes out clean. Remove from oven and let cool for 5 minutes. Drizzle glaze evenly over the top.