Preheat your oven to 350°F. Grab an 8x8-inch baking dish or small cast-iron skillet and lightly coat it with that melted butter. I personally prefer the skillet because it looks prettier on the table, but honestly, either works fine. You're basically just preventing sticking and creating a golden base.

In a large mixing bowl, combine your softened cream cheese, sour cream, and mayonnaise. Blend these together until you've got a smooth, creamy base—no lumps. This usually takes about 2 minutes of stirring with a wooden spoon. Don't use cold cream cheese or you'll be mixing forever.

Fold in your mozzarella and Parmesan cheeses, stirring until everything's evenly distributed. The mixture should start looking rich and creamy at this point. Now add your minced garlic, onion powder, and black pepper, mixing until you can't see any streaks.

Gently fold in your chopped spinach and artichoke hearts using a spatula or wooden spoon. Keep the motions slow and careful so you don't overmix—you want some texture still visible. The mixture might look a little loose, but it'll thicken up during baking.

Pour your spinach artichoke dip classic mixture into your prepared baking dish, smoothing the top with a spatula. Make sure it's spread evenly so it'll cook uniformly. If you see little lumps, just gently push them into the mixture.

Slide the dish into your preheated oven and bake for 25 minutes. The top should look golden and slightly bubbly around the edges when it's done. I always set a timer because I've absolutely walked away and forgotten it—don't be like me.

Pull the dip out and let it rest for 3-5 minutes before serving. This gives the creamy party dip time to set slightly so it's easier to scoop. If it looks too thin when you first remove it, don't panic—it continues to firm up as it cools a bit.