In a large mixing bowl, combine the milk, granulated garlic, and onion powder. Let this mixture sit for 5 minutes to allow the flavors to bloom before adding the rest of the ingredients for the meatballs. Gently mix until just combined; do not overmix or overwork the meat, as this can result in tough, dry meatballs.

Cover the meat mixture with plastic wrap and refrigerate for at least 30 minutes to allow the flavors to meld and the breadcrumbs to soak up moisture.

Preheat the oven to 425°F (220°C). Line a rimmed baking sheet with foil and spray it with nonstick spray, or line the baking sheet with parchment paper.

Wet your hands with water or a little olive oil to prevent sticking and form the meat mixture into 1 1/2-inch meatballs. Don't compact them too tightly.

Place the meatballs on the prepared baking sheet and bake in the preheated oven until they reach an internal temperature of at least 165°F (74°C), about 10 to 15 minutes. Turn the meatballs midway through cooking for even browning.

While the meatballs are baking, prepare the marinara sauce: Place a large saucepan (do not use cast iron, as tomato acidity may cause a metallic taste) over medium heat and allow it to warm up. Pour in the extra-virgin olive oil. When the oil is hot, add the garlic. Reduce the heat to medium-low, allowing the garlic to color slightly and become fragrant. Stir occasionally to prevent burning. Remove the sliced garlic from the oil with a slotted spoon and discard it.

Carefully add the tomato puree and diced tomatoes to the pot. Be cautious as the pot can splatter if it's too hot. Add the Italian seasoning, dried basil, red pepper flakes, salt, and ground black pepper and stir to combine. Bring the sauce to a slow simmer. Cover the pot and cook for at least 25 to 30 minutes, adjusting the heat if necessary to maintain a slow simmer. Simmering allows the flavors to develop, and longer simmering is even better.

Taste the sauce. If it tastes too acidic, you can add some or all of the sugar to balance the natural acidity of the tomatoes.

When the meatballs are done, remove them from the oven and reduce the oven temperature to 350°F (175°C).

Spread a layer of the prepared marinara sauce in the base of an ovenproof dish. Distribute the baked meatballs over the sauce and spoon some additional marinara sauce over each meatball. Sprinkle the shredded Italian cheese blend evenly over the top.

Bake for another 5 to 10 minutes, until the cheese is thoroughly melted and bubbly.

While the cheese is melting, toast the Italian breadcrumbs in a pan with the butter until they smell nutty and begin to brown, stirring frequently so they do not burn. Remove the breadcrumbs from the pan.

Remove the meatballs from the oven and sprinkle with the toasted breadcrumbs and chopped parsley.