Preheat oven to 350F degrees. Line a baking sheet with parchment paper.
In a bowl, combine 2 ½ Tablespoons melted butter, ¼ cup brown sugar, 1 Tablespoon granulated sugar, and 2 Tablespoons corn syrup and stir until blended. Stir in 1 cup oats and ¼ cup nuts, mixing well.
To form the Crisps, drop the oats mixture, about 1 Tablespoon per cooking, rounded, onto the prepared baking sheets, spacing them about 2 ½ inches apart.
Bake 10-12 minutes, rotating the baking sheet 180 degrees at the midway point, until golden brown and bubbly. Watch the cookies during the last couple of minutes to make sure they don't burn since many ovens run hot. Let cool for 5 minutes on the baking sheet. Then, using a metal spatula, transfer the crisps to a large flat plate or sheet of parchment to cool completely.
If topping with nuts after baked, place the nut on the cookies immediately out of the oven, pressing into the cookie gently.
If molding the cookies into cookie "taco", after cookies have cooled about 3 or 4 minutes, start to test the cookie with a metal spatula to see if it holds together. Once it is malleable, fold in half and place a measuring spoon or wooden spoon under the top fold to keep its shape until hardened and cooled.
If serving with creme fraiche or yogurt and fruit, place one cookie on a plate, add fruit and creme fraiche or yogurt and then top with second cookie. Sprinkle with lemon zest, if desired.