Chef John's Meatball-Inspired Meatloaf

Preheat your oven to 325°F (165°C). Grease a 9x13-inch baking dish.

Heat olive oil and butter in a large skillet over medium-high heat. Add onion with a pinch of salt, and sauté until golden brown and soft, about 5 to 10 minutes. Stir in garlic and cook for another 30 seconds, or until fragrant. Remove from heat and let the onion mixture cool to room temperature.

Place breadcrumbs in a large bowl. Pour in the milk and mix with a fork until fully combined. Let the mixture sit for 15 to 20 minutes, allowing the breadcrumbs to absorb the milk.

In a bowl, combine ground chuck, cooled onion mixture, parsley, Parmesan cheese, eggs, 2 teaspoons of salt, black pepper, and cayenne pepper. Squeeze out any excess milk from the breadcrumbs, then add them to the ground chuck mixture, discarding the remaining milk. Mix until everything is evenly incorporated.

Transfer the meat mixture to the prepared baking dish, shaping it into a 3x4x10-inch loaf. Pour tomato sauce over the top and let it flow into the bottom of the dish.