Adjust oven rack 6 inches from broiler element and preheat broiler on high setting.

In a large bowl, combine bread and milk and let sit until bread is softened and milk is absorbed, about 5 minutes.

Using a fork, mash bread mixture until it forms a paste.

Add ground beef, ground pork, cheese, parsley, Worcestershire sauce, garlic powder, onion powder, and oregano.

Using clean hands, gently mix until thoroughly combined.

Divide meat mixture into 8 equal portions. Gently shape each portion into a ball, pressing just firmly enough for it to hold together.

Heat a 12-inch heavy-bottomed stainless steel, carbon steel, or cast iron skillet over medium heat for 3 minutes. Increase heat to high. Add oil and swirl to coat skillet.

Season 2 meatballs evenly with ¼ teaspoon kosher salt and ¼ teaspoon pepper (about ⅛ teaspoon of kosher salt and pepper per patty).

Add seasoned meatballs to skillet and cook, undisturbed, until just beginning to brown on bottom, 30 seconds to 1 minute.

Flip meatballs so browned sides face up.

Using a stiff metal spatula, firmly smash each ball into a patty measuring 4 to 4 ½ inches in diameter and about ½ inch thick, using a second spatula to press down on the first if needed.

Cook patties, undisturbed, until a deep golden-brown crust develops on bottom, about 1 minute.

Using edge of spatula, carefully scrape underneath patties to release them while keeping crust intact.

Flip and cook until second sides are browned, about 1 minute.

Transfer patties to a rimmed baking sheet. Repeat with remaining meatballs, seasoning 2 meatballs with ¼ teaspoon each kosher salt and pepper before cooking each batch.

In a small bowl, whisk together ketchup, brown sugar, and apple cider vinegar.

Spoon about 1 ½ teaspoons glaze over each patty and spread into an even layer with the back of the spoon.

Broil patties until glaze is bubbling and sticky, about 2 minutes.

Serve immediately.