Preheat oven to 350°F (175°C).

In a large bowl, combine eggs, milk, ketchup, cornflakes, dried minced onion, mustard, salt, and pepper.

Add ground beef to the bowl.

Mix well until all ingredients are evenly distributed.

Line a 12-cup muffin tin with foil liners or grease thoroughly.

Press the meat mixture firmly into each muffin cup, filling each cup evenly.

Bake in the preheated oven for 25 minutes, or until a thermometer inserted into the center registers 160°F (71°C).

Remove from oven and drain any excess grease from the muffin cups.

If desired, drizzle with additional ketchup before serving.