Activate the yeast: In a small bowl, mix yeast with warm water (110°F) and let sit for 5 minutes until foamy.
Prepare wet ingredients: In a large bowl, combine sliced butter, sugar, and salt. Pour in the remaining warm water and let sit.
Make the dough: Whisk the butter mixture, then add egg yolk and yeast mixture. Stir in flour until just combined.
Prepare the baking dish: Brush 2 tablespoons of melted butter inside a 9×13-inch dish. Spread dough evenly and let rest for 15 minutes.
Assemble: Preheat oven to 350°F. Brush remaining melted butter over the dough. Sprinkle mozzarella, parmesan, garlic salt, and oregano on top.
Bake: Bake for 28-31 minutes until golden brown and bubbly.
Cool & slice: Let rest for 10 minutes before cutting into 8 breadsticks.
Serve: Enjoy warm with marinara sauce for dipping.