Preheat oven to 350°F. Grease a 13" x 9" baking pan.
Whisk together cake flour, baking powder, salt and cinnamon; set aside. Cream butter with both sugars until light and fluffy, about 3 minutes. Add the eggs and vanilla to the butter mixture and mix until smooth and incorporated. Add the dry ingredients and mix until just incorporated. Add the pecans and toffee. Spread evenly in the pan and bake for about 35 minutes, rotating the pan once halfway through.
When blondies are done they will turn a dark caramel color; a toothpick inserted into the middle of the pan should come out almost clean, with some moist crumbs.
Recipe by dramatic pancake at https://www.dramaticpancake.com/alex-toffee-pecan-blondies/