Heat the oven to 325°F with the racks in the upper- and lower-middle positions. Line 2 baking sheets with kitchen parchment. In a medium bowl, whisk together the flour, baking soda and salt; set aside.

In a small microwave-safe bowl, stir together the cherries and vinegar. Microwave uncovered on high until the cherries absorb the vinegar, about 1 minute; set aside.

In a medium saucepan over medium, melt the butter. Add 1 ounce (¼ cup) of the chopped chocolate and the cocoa, then remove the pan from the heat.

Whisk until the chocolate is melted and the mixture is smooth. Let cool until barely warm to the touch.

In a stand mixer with the paddle attachment, beat the egg and both sugars on medium until light and fluffy, 2 to 3 minutes.

With the mixer running on low, add the vanilla, then slowly pour in the chocolate-butter mixture. Beat on medium until homogenous, 3 to 5 minutes, scraping down the bowl once or twice.

With the mixer running on low, add the dry ingredients, then mix just until combined, about 30 seconds.

Using a silicone spatula, stir in the remaining chopped chocolate, the pecans and the cherries along with any remaining liquid until the ingredients are evenly distributed.

Divide the dough into 24 portions of 2 tablespoons each. Form each into a ball with your hands. Place the balls on the prepared baking sheets, spacing them evenly.

Bake until slightly cracked on top and the edges feel firm, 14 to 16 minutes, switching and rotating the baking sheets about halfway through.

Cool on the baking sheets for 10 minutes, then use a wide metal spatula to transfer the cookies directly to a wire rack. Cool to room temperature.