Preheat the oven to 325 degrees and set the rack to the middle position.
Lightly grease a 9-inch cast iron pan with canola oil.
Mix the fruit, nuts, chocolate and peanut butter chips together in a bowl and set aside.
In a bowl, whisk together the flour, baking soda and salt. Stir in the oats. Set aside.
In a mixer, beat the butter and brown sugar until light and fluffy, about 2-3 minutes. Add eggs and vanilla, scraping down the sides of the bowl as necessary. Add in the flour-oat mixture, and mix well to combine.
Add about 1/3 of the fruit, nut and chips mixture and stir well to combine.
Place half of the cookie dough into the bottom of a cast iron pan and pat in well to cover the bottom of the pan.
Spread remaining 2/3 of the fruit, nut, chips mixture evenly over the layer of dough.
Top with remaining half of the cookie dough and gently press (using damp fingers if necessary) dough evenly over to cover filling.
Bake for about 15-20 minutes, or until cooked as desired.
Recipe adapted from White on Rice Couple.
Feel free to use any combination of fruit and nuts you prefer.
If you have more dough than needed for your pan, form any extra into 1 1/2 inch balls and freeze for cookies later.