1 tablespoon unsalted butter, room temperature, plus 1 1/2 tablespoons
1 large shallot, finely diced (about 1/4 cup)
Kosher salt and freshly ground black pepper
2 medium cloves garlic, finely chopped (about 2 teaspoons)
1/3 cup dry white wine, such as Sauvignon Blanc
1/4 cup crème fraîche
6 medium zucchinis, diagonally sliced 1/2-inch thick
1 tablespoon chopped fresh thyme
1 tablespoon chopped fresh mint
1 tablespoon chopped fresh flat leaf parsley
1 cup fresh breadcrumbs
1/3 cup finely chopped walnuts
1/2 cup grated Gruyère
1/2 cup grated Parmigiano Reggiano
Drizzle of extra virgin olive oil (optional)