1 h 20 min
* PLUS Standing Time: 120 minutes
, coarsely chopped
PREHEAT oven to 325F. Line 2 baking sheets with parchment.
WHIRL nuts with oats and flour in a food processor until finely ground. (It should look like wet sand.) Set aside.
MELT butter with cream and sugar in a medium saucepan set over medium. Bring to a simmer, then whisk constantly for 1 min. Scrape butter mixture into food processor with ground nuts. Whirl until smooth, about 30 sec. Batter will be hot. Drop heaping teaspoonfuls of batter on prepared sheets, at least 2 in. apart. Cookies will spread as they bake.
BAKE in centre of oven, 1 sheet at a time, until edges and centre of cookies are dark golden, 13 to 15 min. Cool cookies on sheet for 2 min, then transfer to a wire rack to cool completely. Repeat with remaining batter.
MELT chocolate in a microwave-safe bowl on medium, stirring halfway through, until almost melted, about 1 min. Stir until completely melted. Let stand until cool, but still spreadable, 10 to 12 min. Drop 1/2 tsp of melted chocolate on the bottom of each cookie. Using a palette or butter knife, thinly spread chocolate right to the edges. Return to rack, chocolate-side up. Use the tip of a fork to make a wave pattern across the chocolate on all cookies. Then sprinkle with salt. Let stand until chocolate is firm, about 2 hours. Cookies will keep well, stored in between sheets of wax paper, in an airtight container at room temperature, up to 5 days or freeze up to a month.