Colombian Arepas con Queso with Crispy Golden Crust and Gooey Cheese

Ingredients

• 2 cups masarepa flour
• 2 teaspoons salt
• 2 teaspoons sugar
• 2 tablespoons unsalted butter, at room temperature
• 1½ cups mozzarella cheese, freshly shredded
• ¼ cup whole milk
• 2½ cups lukewarm water
• 1 teaspoon nonstick cooking spray (for skillet)