Prepare macaroni and cheese according to your recipe or package directions, then transfer to an airtight container and refrigerate at least 12 hours (up to 3 days) so it firms up.
About 15 minutes before forming balls, place the chilled mac 'n' cheese in the freezer briefly to chill further.
Place the flour, beaten eggs, and breadcrumbs into three separate shallow bowls.
Preheat the oven to 425°F (220°C). Line two baking sheets with silicone mats, parchment, or foil. Drizzle 1 tablespoon of olive oil onto each sheet and spread it around.
Using a 1-inch cookie scoop or a tablespoon, portion the chilled mac 'n' cheese into roughly 1-inch balls; if needed, shape gently with your hands so they hold together.
Working one ball at a time, roll it in flour to coat, dip briefly in the beaten egg, then roll in breadcrumbs to fully coat. Place each coated ball on the prepared baking sheets, about 10 per sheet.
Bake for 10 minutes, then remove the sheets. Add 1 tablespoon of olive oil to each sheet and spread it, flip the balls, and return to the oven.
Bake an additional 7–10 minutes, until the balls are golden brown and crisp. Remove from the oven and serve immediately with your preferred condiment.
