Preheat oven to 325°. Line several baking sheets with foil, dull side up. Grease foil with softened butter. (Be sure to completely coat foil with butter.)
In a medium bowl, beat together egg, sugars, vanilla extract, and salt with a mixer at high speed until mixture thickens and is pale. Add pecans, oats, and melted butter, stirring well.
Drop approximately 2 teaspoons dough 3 inches apart on prepared baking sheets. Using a fork dipped in water, flatten cookies.
Bake until edges of cookies are deep golden brown, 9 to 11 minutes. Let cool completely on baking sheets. Carefully peel cookies from foil (cookies will peel more easily when cooled). Transfer cookies to a wire rack.
In a small heatproof bowl set over a small saucepan of simmering water, melt together chocolate and shortening, stirring until smooth. Transfer mixture to a pastry bag. Cut a small hole in tip of bag. Drizzle chocolate mixture over cookies. Let stand until set. Store cookies in an airtight container at room temperature for up to 3 days.
Recipe by TeaTime Magazine at https://teatimemagazine.com/chocolate-drizzled-lace-cookies/