Preheat the oven to 350°F and spray your casserole dish with baking spray. (I used a 10x7 casserole dish.)
Cut all the croissants into four equal-sized pieces and cut the ham slices in half.
8 large croissants, quartered
In a bowl, whisk together all the ingredients for the egg mixture until fully combined.
6 large eggs, 1 cup whole milk, 1 tsp garlic powder, 1 tsp salt, ½ tsp paprika, ½ tsp ground black pepper, 1 Tbsp finely chopped chives or greens
Take the croissant pieces and dip them briefly into the egg mixture so they are coated and place them into the casserole dish. Repeat until you have one even layer covering the bottom of the dish. (If you are using a larger casserole dish, you will have only 1 layer.)
Tuck half of the ham slices between and around the croissant pieces, then sprinkle half of the shredded cheese evenly over the top.
6 oz thinly sliced ham, 2 cup shredded cheese, gruyere or white cheddar
Repeat with another layer of dipped croissant pieces, arranging them evenly over the top. Pour any remaining egg mixture evenly over the entire dish.
Add the remaining slices of ham between the croissants, then sprinkle the remaining shredded cheese over the top.
Bake at 350°F for 40-45 minutes, until the tip is lightly golden and the egg mixture is fully set (not runny).
Remove from the oven and let the casserole cool for a couple minutes.
Drizzle with honey mustard sauce, if desired, and immediately while still hot.
honey mustard sauce, optional drizzle