Combine ingredients in large bowl and mix well.
Divide the ground beef mixture equally into 4 mini loaves. Shape each loaf into an oval, roughly 3 1/2 inches long and 2 1/2 inches wide.
Transfer the mini meatloaf ovals to a Medium Ziploc® brand Zip 'n Steam® bag, spacing them evenly in the bag. Seal bag and place in microwave.
Cook on full power for 7 1/2 to 9 minutes until all mini meatloaves are well done throughout. If needed, continue microwaving at 30-second intervals until all mini meatloaves are well done.
Allow bag to stand 1 minute before handling. Carefully open bag and remove mini meatloaves.