In a small bowl, mix the softened butter, minced garlic, and chopped parsley until well combined.: The aroma will be bright and garlicky as the butter takes on the herb notes, and the mixture should look homogenous and slightly glossy. This compound butter forms the aromatic base for toasting the buns, and mixing at room temperature allows the garlic and parsley to disperse evenly. If you skip softening the butter, it will be lumpy and hard to spread, so plan ahead. When the bowl smells fragrant and the color is flecked with green, you know it is ready.
Slice the hamburger buns horizontally and spread with prepared garlic parsley butter evenly on the cut sides.: As you spread, the butter should melt slightly on contact from the warmth of your hands, coating each surface in a thin sheen. This ensures that when toasted, the buns crisp and develop golden edges while carrying savory garlic notes into every bite. Uneven spreading can lead to one spot burning and another remaining pale, so aim for an even layer for balanced toasting.
Heat a skillet over medium heat. Add buns, buttered side down, and toast until golden brown and crisp, about 2-3 minutes total. Set aside.: You will hear a light sizzle as the butter hits the pan, and the aroma will deepen to a roasted garlic scent with hints of parsley. Look for a warm golden color and a slightly firm surface when you press gently. If the pan is too hot the butter may brown and burn quickly, so keep the heat steady to avoid a bitter, charred flavor.
In a large mixing bowl, combine ground beef, onion, garlic powder, Italian seasoning, salt, and black pepper. Mix to combine evenly.: As you fold the mixture, the scent of onion and dried herbs will lift out, and the meat should look uniformly seasoned but not overworked. Proper mixing ensures even seasoning distribution, which translates to consistent flavor in every patty. Over mixing can make patties dense and tough, so combine until ingredients are just incorporated.
Divide beef mixture into four equal portions and shape them into burger patties, ensuring they are slightly larger than the size of your hamburger buns.: When shaping, you should feel the meat hold together without compressing it too firmly, and the patties should be slightly thinner at the edges so they cook evenly and do not domed up. A slight indentation in the center helps prevent puffing. If the patties are packed too tight they will be compact and dry, so be gentle while forming them.
Heat olive oil in a skillet over medium-high heat. Once the oil is hot, add the burger patties and cook for about 4-5 minutes on each side, or until they are cooked to the desired level of doneness.: The skillet should hiss when the patties touch the surface, and you will see a rich brown crust forming along the edges as natural sugars caramelize. This crust provides flavor and texture contrast to the juicy interior. Resist pressing the patties while they cook, as that forces juices out and dries them. Use a meat thermometer if you want precision for doneness.
During the last minute of cooking, spoon a generous amount of pizza sauce onto each burger patty, sprinkle chopped basil leaves, followed by a slice of mozzarella cheese, and top with pepperoni. Allow cheese to melt.: The sauce will steam gently and the cheese should begin to soften and spread, creating a glossy, molten layer. The basil will release a fresh herbal perfume, and the pepperoni will warm and render some oils, adding savory pockets. Watch closely to melt the cheese without scorching the pepperoni, and avoid removing the patties too soon or the cheese will not reach that satisfying stretchiness.
Transfer cooked burgers to the bottom half of each toasted bun. Serve pizza burgers immediately, while they are still warm and the cheese is gooey.: As you assemble, you should notice steam rising from the cheese and sauce, and the contrast between the crisped bun and the moist patty is at its best when served hot. Immediate serving preserves the gooey texture and prevents the bun from becoming soggy. If you let them sit too long, the bun will absorb the sauce and lose its crisp edge, so time plating so guests can enjoy the intended textures.
