Preheat the oven to 375°F. Lightly grease 2 baking sheets or line with parchment. , In a stand mixer fitted with the flat beater or working with a hand mixer in a large bowl, beat together the butter and sugar until well mixed, 2 to 3 minutes. Add the egg, vanilla, cinnamon, and salt, then beat until fluffy, another 1 to 2 minutes, scraping the bowl as needed. , Beat in the flour, baking powder, baking soda, and oats until well combined. , Mix in the fruit and nuts until evenly incorporated. , Scoop the dough into golf ball-sized rounds of dough (about 2 tablespoons/40g each); a jumbo cookie scoop works well here. Distribute the dough balls evenly between the 2 pans (12 cookies per pan), spacing them about 1 1/2" apart. , Using your hands, flatten the dough into pucks about 2" in diameter and 1/3" to 1/2" thick. If the dough starts to stick, lightly wet or grease your hands., Bake for 15 to 16 minutes for soft cookies, or until just set around the edges and pale in the center, or 18 to 20 minutes for crunchy cookies, or until golden brown. Halfway through baking, rotate the pans from front to back and top to bottom. , Remove the cookies from the oven and let them cool on the pan before serving at room temperature. (Cookies are fragile until cool.), Storage information: Store leftover oat cookies in an airtight container, at room temperature, for several days. If you want to keep them soft and chewy, store them with a brown sugar saver or with a slice of white bread. Freeze for longer storage.