Mix eggs: In a bowl mix milk, eggs, salt, and pepper. Whisk until it is mixed thoroughly. Mix in bread and let it rest of 15 minutes for the bread to absorb the mixture of eggs and milk.
Prepare mold and oven: Heat oven to 350 °F [175 ºC]. Grease a non-stick baking pan (8" diam [20 cm diam.]) with the butter.
Add vegetables: Add 1 1/4 cup of cheese, bell pepper, leek and pancetta to the bread, mix well. Pour the bread mixture into the baking pan. Cover with aluminum foil.
Cook: Bake for 20 minutes. Remove from the oven, remove the aluminum foil and top with the broccoli, and sprinkle the rest of the cheese. Return to the oven and cook until the cheese melts [5-10 mins].
Serve: Remove from the oven, loosen the edge with a knife and let it rest for a couple of minutes before removing from the pan. Serve warm.
I like my broccoli crispy, if you want yours softer you may cover with the aluminum foil the next time you return to the oven, you may need to cool longer.