Preheat the oven to 375 degrees and lightly grease a mini muffin tin.
Bring a pot of water to a boil and cook the macaroni until al dente. Drain and set aside.
Steam the cauliflower florets for 5 minutes until tender, then chop them into very small pieces.
In a skillet over medium heat, melt the butter and whisk in the flour. Cook for 1 minute, then slowly whisk in the milk until the mixture thickens.
Stir the mozzarella cheese into the sauce until melted. Add the salt and black pepper.
In a mixing bowl, combine the cooked macaroni, chopped cauliflower, cheese sauce, and egg. Mix well.
Spoon the mixture evenly into the prepared mini muffin tin, pressing down gently.
Bake for 18 to 20 minutes until the tops turn golden. Let the bites cool for 5 minutes before removing them from the tin.
Place two olive slices on each bite to form eyes.