In a large mixing bowl or the bowl of a stand mixer, mix butter and granulated sugar on high speed until smooth and creamy, about 30 seconds. Add all purpose flour and fine sea salt, and mix on low speed until mixture resembles breadcrumbs, about 30 seconds more.

With a bench scraper, work in the dark chocolate and chopped pecans. Use your hands to finish bringing the ingredients together until a soft dough forms.

Shape dough into a log, approximately 9 long and about 2 inches in diameter. Wrap in clingfilm/plastic wrap and refrigerate until firm, at least 1 hour, or overnight.

Preheat oven to 355° F (180° C). Line a half sheet rimmed baking tray with parchment or a silicone baking mat.

Unwrap log. With a sharp chef’s knife, slice into 1/2-inch-thick slices. You should have about 18 slices total.

Arrange on prepared tray. Sprinkle with coarse or flaky sea salt.

Freeze tray for 10 minutes, or refrigerate for 30 minutes if your tray doesn’t fit in the freezer.

Bake in preheated for 20-22 minutes, or until very lightly golden brown around the edges

Remove from oven. Transfer to a wire rack to cool completely.

Store chocolate pecan shortbread biscuits in an airtight container at room temperature for up to 5 days, or freeze for up to 3 months.