Preheat oven to 300°.

Line baking sheets with Silpats (French nonstick baking mats).

In the bowl of an electric mixer fitted with the paddle attachment, beat butter and sugar on medium speed until light and fluffy, about 2 minutes.

Add flour a half cup at a time, mixing on low speed until well combined.

Remove bowl from mixer; with a wooden spoon or your hands, stir in coconut, sesame seeds, and pecans.

Divide dough into thirds.

Roll into logs about 1 1/2 inches in diameter.

Wrap each log in plastic, and refrigerate until very firm, about 2 hours.

Using a sharp knife, cut logs into 1/4-inch-thick slices.

Transfer to prepared baking sheets, about 1 1/2 inches apart.

Bake until edges are golden, 20 to 30 minutes.

Transfer sheets to a wire rack to cool.

Cool for 5 minutes on baking sheets before transferring cookies to wire racks to cool completely.