- 2 cups old-fashioned rolled oats (not quick-cooking)
- 1 cup all-purpose flour, spooned and leveled
- ¾ teaspoon baking soda
- ¼ teaspoon ground cinnamon
- 2 teaspoons flaky sea salt (such as Maldon)
- ½ cup (1 stick) unsalted butter, at room temperature
- 4 tablespoons vegetable shortening
- ½ cup granulated sugar
- ½ cup packed light brown sugar
- 1 large egg
- 1 teaspoon pure vanilla extract
- 6 ounces bittersweet chocolate, coarsely chopped
- Heat oven to 375° F with the rack in the upper and lower thirds. Line 2 large baking sheets with parchment.
- Combine the oats, flour, baking soda, cinnamon, and 1 teaspoon of the salt in a medium bowl; set aside.
- Beat the butter, shortening, granulated sugar, and brown sugar with an electric mixer on medium-high speed until lightly and fluffy, 2 to 3 minutes. Beat in the egg and vanilla. Reduce the mixer speed to low and gradually add the flour mixture, mixing just until combined (do not overmix). Stir in the chocolate.
- Drop heaping tablespoonfuls of the dough onto the prepared baking sheets, spacing them 2 inches apart. Sprinkle with the remaining 1 teaspoon of salt.
- Bake, rotating the pans halfway through, until lightly brown around the edges, about 10 to 12 minutes. Cool slightly on the baking sheets, then transfer to a wire rack to cool completely.
- Storage suggestion: Keep the cookies at room temperature in an airtight container for up to 5 days.