Preheat oven to 350 degrees. Cut the bread lengthwise and widthwise without cutting through the bottom crust. This can be a little tricky going the second way but the bread is very forgiving. Place on a foil-lined baking sheet. Insert cheese slices between cuts. Combine butter, onion, and poppy seeds. Drizzle over bread. Wrap in foil; place on a baking sheet. Bake at 350 degrees for 15 minutes. Unwrap the bread and bake 10 more minutes, or until cheese is melted. Variation: Bloomin Pizza Bread 1 unsliced round loaf sourdough bread 12-16 ounces mozzarella or Provolone cheese, thinly sliced 1 (3.5 ounce) package pepperoni, halved 3 Tablespoons butter, melted 1/2 teaspoon garlic powder 1/2 teaspoon Italian seasonings 2 Tablespoons Parmesan cheese pizza/marinara sauce for dipping