whole garlic head • extra- virgin olive oil • sea salt, plus more as needed • freshly ground black pepper, plus more as needed • littleneck clams, scrubbed • (2 sticks/226g) unsalted butter, softened • chopped fresh tender herb leaves, such as thyme, parsley, and chives, plus more for garnish • sourdough bread • champagne or any dry sparkling white wine • Flaky sea salt, for serving • Lemon wedges, for serving