Equipment Needed
- Large mixing bowl
- Rimmed baking sheet
- Parchment paper or silicone baking mat
- Small bowl (for glaze)
- Wire rack (optional, but helps with browning)
Step-by-Step Instructions
First, I get my oven heating to 375°F (190°C) and line my baking sheet with parchment paper. In my large bowl, I combine the milk and panko breadcrumbs and let them sit for a minute to soften—this is a little trick that helps keep the meatloaf mixture tender. Then, I add the grated onion, minced garlic, egg, 2 tablespoons of ketchup, Worcestershire sauce, Italian seasoning, salt, and pepper. I use my hands to mix it all gently but thoroughly. The key here is not to overwork the meat, which can make the bites tough. I just mix until everything is evenly combined, no more.
Now for the fun part: the cheese stuffing. I scoop out about 2 tablespoons of the meat mixture and flatten it slightly in my palm. I press one cube of mozzarella into the center, and then I carefully fold and pinch the meat around it, rolling it gently between my palms to form a sealed ball. I place each ball seam-side down on the prepared baking sheet. This part can be a little messy, but I promise it’s worth it! I make sure the balls aren’t touching on the sheet so they can brown nicely all around.
While the meatballs are being formed, I whisk together the glaze in a small bowl: the 1/2 cup ketchup, brown sugar, and apple cider vinegar. The vinegar adds a necessary tang that cuts through the richness—don’t skip it! Once all my meatballs are snug on the baking sheet, I brush each one generously with this glaze. I’ve tried spooning it on and brushing, and brushing gives a much more even, beautiful coating.
Into the oven they go for about 20-25 minutes. The smell is just incredible. You’ll know they’re done when the tops are caramelized and glossy, and the meat is cooked through. I always do a test cut on one after it rests for 5 minutes—the cheese should be gloriously melted and stringy. That rest time is important; it lets the juices redistribute so they don’t all spill out on the first bite.(See the next page below to continue…)