Prepare the Mac and Cheese:

In a saucepan, melt the butter over medium heat. Stir in the flour and cook for 1-2 minutes to form a roux.
Gradually whisk in the milk until the mixture is smooth. Cook, stirring continuously, until the sauce thickens.
Remove from heat and stir in the cheddar and Parmesan cheeses until melted and smooth. Season with salt, pepper, and paprika or mustard powder if using.
Fold in the cooked macaroni until well coated. Let the mixture cool, then refrigerate until firm, at least 2 hours or overnight.

Form and Bread the Bites:

Preheat your oven to 400°F (200°C) and grease a baking sheet.
Shape the chilled mac and cheese into small balls, about 1-inch in diameter.
Dip each ball into the beaten eggs, then roll in breadcrumbs to coat evenly.

Bake:

Place the breaded mac and cheese bites on the prepared baking sheet. Spray lightly with cooking spray or drizzle with a little oil for extra crispiness.
Bake for 15-20 minutes, or until golden brown and crispy, turning halfway through for even browning.

Serve:

Let the bites cool slightly before serving. Serve with dipping sauces like marinara, ranch, or your favorite sauce.