Preheat the oven to 400°F. Lightly spray a standard 10-cup bundt cake pan with nonstick cooking spray. Set it aside.
Evenly layer the cubed French bread in the bottom of the prepared pan.
Evenly layer the potatoes on top of the bread layer.
Evenly layer the diced ham on top of the potatoes.
Evenly sprinkle the diced onions on top of the ham.
Evenly sprinkle the shredded cheese on top of the onions.
Evenly sprinkle the kosher salt and pepper over the cheese layer.
Using a medium-sized mixing bowl, whisk together the eggs and milk. Slowly pour over the top of the bundt ingredients.
Bake uncovered on the middle rack of the oven for 45 to 50 minutes.
Allow the breakfast bundt cake to rest for 5 minutes.
Place a flat, heat-safe dinner plate on top of the bundt pan. Using pot holders, grasp the edges of the plate and the lip of the bundt pan, and carefully flip the plate and pan over. Remove the bundt pan and slice ten 2-inch servings. Serve immediately.
A good way to tell if the eggs and milk are well incorporated is when the mixture begins to show large bubbles, it is ready to pour. You must pour the egg mixture slowly, or the egg may go everywhere.
Don’t overfill the bundt pan. During baking, the bundt cake will expand and rise.
Place the bundt pan on a baking tray in the oven in case you end up with any egg bubbling over.
Oven temperatures vary and may need to be recalibrated periodically to ensure they are accurate. Make sure to check your breakfast bundt cake at the lower end of the recommended baking time.