Preheat oven to 325° F. Spread Silver Palate Thick and Rough Oatmeal in a thin layer on a baking sheet and toast until lightly colored, 15 minutes. Set aside to cool. Cream butter and brown sugar together in a medium bowl until light and fluffy. Stir in eggs, vanilla, coconut and lemon zest. Sift flour, salt, baking powder, cinnamon and coriander over butter mixture and blend well. Blend in oatmeal and dates. Lightly grease 2 baking sheets or line with parchment. Drop dough by slightly rounded tablespoons onto pans, leaving about 3 inches between cookies. Bake in middle of oven until edges are lightly browned, 16 to 18 minutes. Remove from oven and let cookies cool on pan for 5 minutes before transferring to racks to cool completely.