1 round (about 1 pound) loaf firm sourdough bread
1/2 cup (4 ounces or 115 grams) salted or unsalted butter
1/2 teaspoon coarse or flaky salt, or 1/4 teaspoon table salt (if butter is unsalted)
4 medium cloves garlic, minced
Pinch or two of red pepper flakes or freshly ground black pepper to taste
1 cup finely grated cheese (I used a mix of 2/3 firm aged cheeses — pecorino and asiago — and 1/3 fontina for meltiness)
1 teaspoon finely minced fresh herbs (I used 1/2 each rosemary and oregano; use more to taste)
1 tablespoon extra fresh herbs (such as chives or parsley) to finish (optional)