8-10 ounces Pacific cod (see Note) or tilapia fillets, cut into 2 pieces
1 1/2 teaspoons chopped fresh thyme, divided
1/4 teaspoon salt, divided
1/8 teaspoon freshly ground pepper
1 1/2 teaspoons extra-virgin olive oil
1/2 shallot, chopped
1 clove garlic, minced
6 tablespoons white wine
1 cup canned diced tomatoes
2 tablespoons heavy cream or half-and-half
1/4 teaspoon cornstarch