Make It Now:

1. Preheat oven to 450° F. Generously spray a 12-cup muffin tin with cooking spray.
2. Heat oil in a medium sauce pan over medium-high heat. Saute the onion and carrot until vegetables are softened, about 3-4 minutes. Add the garlic for another 30-60 seconds. Remove from the heat. Stir in the salt, pepper, chicken stock, Worcestershire sauce, and tomato paste and allow the mixture to cool.
3. In a large bowl, use your hands to combine the cooled veggie mixture, ground beef, parsley, egg, and bread crumbs. Do not over mix. 
4. Use a spoon or ice cream scoop to fill each muffin tin hole to the top. Gently press to fit into muffin tin mold.
5. Top each mini meat loaf with a spoonful of ketchup and spread it around with the back of the spoon. (Freezing instructions for Method #1 begin here.)
6. Bake about 20-25 minutes. Cut open a muffin to test that the middle is cooked through (no more pink or registers 165°F internally). Sprinkle with a little chopped parsley at the end, as garnish. (Freezing instructions for Method #2 begin here.)

Freeze For Later:

Method #1 (Uncooked): Follow instructions through Step 5 but DO NOT bake. Wrap the muffin tin with plastic wrap and a layer of foil and freeze.

Method #2 (Fully Cooked): Fully cook and cool the muffins. Place in a flat gallon-sized freezer bag in a single layer. Squeeze out excess air, seal and freeze flat.

Prepare From Frozen:

Method #1 (Uncooked): Thaw in the refrigerator for 24-48 hours. Set muffin tin out on the counter for about 20 minutes before baking. Bake according to directions, but increase baking time if muffins are still partially frozen or really cold. They register 160° F internally when done or have no more pink inside.

Method #2 (Fully Cooked): Wrap in a moist paper towel. Warm in the microwave using the defrost setting or by microwaving in 30 seconds increments, until warmed through.