Combine the flour, oats, baking soda and salt in a large bowl and set aside. In a stand mixer fitted with a paddle attachment, cream the butter and brown sugar until light and fluffy. Add the yogurt and vanilla and mix on medium-low speed. Add the egg and stir to combine. Add the dry ingredients, and mix on medium-low speed until combined. Stir in the chocolate chips and cherries by hand. Refrigerate for 30 minutes.
Using a 1-inch cookie scoop, scoop the dough into balls. Add one ball to each mini cast-iron skillet. Bake until the cookies are golden brown around the edges and soft in the center, 13 to 15 minutes. (Alternatively, drop the dough balls onto parchment-lined baking sheets¿about 8 per sheet¿and bake for the same amount of time.)
Refrigerate or freeze any leftover cookie dough for later use.