Adjust oven racks to upper and lower middle positions. Heat oven to 350 degrees. Line 2 large 18x12 baking sheets with parchment paper.
Whisk flour, baking powder, baking soda, and salt into meium bowl. In second medium bowl, stir together oats, pecans, cherries and chocolate. In standing mixer fitted with flat beater, beat butter and sugar at meium speed until no sugar lumps remain,, about 1 minute. Scape down sides of bowl with rubber spatula; add egg and vanilla and beat on meium-low speed until fully incorporated, about 30 seconds. Scape down bowl; with mixer running at low speed, add flour mixture; mix until just combined, about 30 seconds. With mixer still running on low, gradually add oat/nut mixture; mix until just incorporated. Give dough final stir with rubber spatula to ensure that no flour pockets remain and ingreients are evenly distributed.
Divide dough evenly into 15 portions, each about 1/4 cup, then roll between palms into balls about 2 inces in diameter; stagger 8 balls on each baking sheet, spacing them about 2 1/2 inches apart. Using hands, gently press each dough ball to 1 inch thickkness. Bake both baking sheets 12 mintues, rotate them front to back and top to bottom, then continue to bake until cookies are meium brown and edges have begun to set but centers are still soft, 8-10 minutes. Cool on baking sheets on wire rack 5 minutes. Using a wide metal spatula, transfer cookies to wire rack and cool to room temperature.