Either cut the French bread into squares or just rip up piece about 1 inch large and put into a greased 8x8 casserole dish.
In a large bowl, whisk eggs, half & half, vanilla, and cinnamon. Pour over cut up bread pieces.
Using your hands, lightly push the bread mixture down into the casserole dish to make sure every piece will soak in the egg mixture. Sprinkle ½ to ¾ cup of blueberries on top of soaking bread.
In the same bowl used earlier, blend butter, brown sugar, corn syrup, pecans, and oats until evenly mixed.
Evenly lay dollops of oatmeal mixture on top of blueberries. Press down lightly to get into all the holes. Blueberries can stick out and not all have to be covered.
Cover and set in refrigerator for four hours or overnight.
Preheat oven to 375 °F and bake covered for 45 minutes.
Remove cover on casserole dish and turn off oven. Leave dish cooking for another 15 minutes.
Take out of oven and let set for 10 minutes. Slice and enjoy with a few leftover blueberries on top.