Whisk both flours, baking powder, baking soda, salt & cardamom in a medium bowl.
Using an electric mixer, beat butter & both sugars on high speed until light & creamy. 2-3 minutes. Add eggs one at a time, beating to blend & scraping down bowl between additions. Beat in vanilla.
Reduce speed to low. Gradually add dry ingredients & mix just until combined. Fold in oatmeal & fruit.
Divide dough between 2 large sheets of parchment paper. Using paper as an aid, roll up each piece of dough into a 1 1/2-inch diameter log. Wrap in plastic; freeze for at least 4 hours up to 3 weeks.
When ready to bake: Preheat oven to 350 F. Unwrap dough & cut into 1/2-inch thick rounds. Roll edges of rounds in ground flax seed. Place 2-inches apart on a parchment paper lined baking sheet.
Bake until edges are golden brown, 15-18 minutes. Transfer to a wire rack; let cool. Store in an airtight container or freeze.
Recipe Notes
Any fruit, nuts or seeds should be chopped quite small so your cookies can be sliced frozen.
Rolling the edges in ground flax seed gives them such a nice flavor.