Coconut Oatmeal Lace Cookies

For cookies:

• 1 stick unsalted butter
• 1/2 cup packed light brown sugar
• 1/4 teaspoon salt
• 3/4 cup sweetened flaked coconut
• 3/4 cup rolled oats
• 1/4 cup all-purpose flour

For decorating:

• 3 ounces fine-quality bittersweet chocolate, finely chopped and melted
• 3 ounces fine-quality white chocolate, finely chopped and melted

• Equipment: 2 (17-by 11-inch) nonstick bakeware liners such as Silpats; 2 heavy-duty sealable bags