Start by preheating your oven to 350 degrees Fahrenheit. While it's warming up, lightly grease your 9x13-inch baking dish with butter or cooking spray. I use a silicone brush with soft butter—it goes on evenly and prevents any sticking. Get every corner and the sides. This step matters more than you'd think.

Pour the milk, melted butter, and eggs into a medium mixing bowl. Add the Bisquick and salt. Using a whisk or fork, blend everything together until the mixture is smooth and fairly uniform. You want to break up any lumps of Bisquick, but don't overbeat. A few tiny lumps are actually fine—they'll disappear in the oven. The batter should look like thick pancake batter.

Now stir in the diced ham, chopped broccoli, Cheddar cheese, American cheese, black pepper, and garlic powder if using. Fold gently until everything is distributed throughout the batter. The mixture will look chunky and textured, which is exactly what you want. Every bite should have something interesting happening.

Carefully pour the entire mixture into your prepared baking dish. Use a rubber spatula to spread it evenly. Don't obsess over perfection here—it'll level out as it bakes. Just make sure nothing is piled too high in one corner.

Slide the dish into your preheated oven and bake for 40 to 45 minutes. You're looking for a golden-brown top and a center that's set but still has a tiny bit of jiggle—not raw, but not completely firm. A toothpick inserted in the center should come out clean or with just a tiny bit of custard clinging to it. The edges will pull slightly away from the pan when it's done. Let it rest in the pan for 5 to 10 minutes before slicing. This makes it much easier to cut clean pieces without everything falling apart. It also lets the custard set up just a bit more.