Using a large bowl, whisk together the melted butter, eggs, milk, maple syrup, brown sugar, vanilla, cinnamon, cardamom and nutmeg.
Add bagel pieces to the bowl and toss until well combined.
Cover and refrigerate at least 1 hour. (Note: This can be refrigerated overnight for an easy breakfast.)
For the Topping
Preheat oven to 350°F.
Spray a 9”x13” baking pan with non-stick baking spray. Transfer the bagel mixture into the baking pan.
Using a small bowl, combine the flour, sugar and cinnamon; stir until well combined.
Cut the butter into small cubes. Using two butter knives or a pastry cutter, cut the butter into the dry mixture. Sprinkle this mixture on top of casserole before baking.
Bake casserole for 85-90 minutes, or until fully baked. (Note: Peek at the casserole during the last 10-15 minutes. If the top is beginning to burn, tent with foil for the remaining baking time.)
Remove casserole from oven and let cool for 10-15 minutes.
For the Glaze
Using a small bowl, whisk together the confectioner’s sugar, maple syrup and milk. Drizzle glaze on top of casserole.
Sprinkle berries on top before serving.
Notes
Cinnamon raisin bagels worked great in this casserole, but I could see other sweet flavors (like blueberry) working well, too.