Toast the walnuts using your favorite method. Mine is to put them on a paper towel, microwave on high for 30 seconds, shuffle them around and repeat until they release their oils. Let cool and chop.
Grind the oatmeal in a small coffee grinder or processor and set aside.
Mix flour, baking powder, baking soda and salt, set aside.
Beat butter and both sugars until creamy. Add egg and vanilla and stir until mixed.
Add flour mixture gradually, stirring until incorporated. Stir in oat flour until blended, then add chocolate chips and toffee and stir to make a soft dough.
Scoop dough up with a quarter cup measure and shape into 12 or 13 large rounds. Press them slightly to make discs. Set the discs on a plate and chill for a few hours or until firm.
Place on parchment lined cookie sheets about 3 inches apart. Bake in a well preheated oven at 375 degrees for about 12 to 15 minutes.
Let the cookies cool completely before serving. These taste better after they've cooled (in my opinion).