Preheat oven to 350 degrees. Line 9 x 13 baking pan with foil, leaving enough over hang to lift out bars later. Spray foil with non-stick cooking spray.

Combine flour, oats, nuts, sugars, baking soda and salt together in a large bowl for a stand mixer. Using paddle attachment, beat butter into flour mixture at low speed, until it looks like wet sand, about two minutes.

Firmly press two-thirds of the mixture into the bottom of the foil lined pan. Bake for 20 minutes. remove and while still hot, spread strawberry preserves over crust. Top with remaining mixture and bake for an additional 30 minutes until bubbling and starting to brown.

Let bars cool for 1-2 hours then lift from pan and cut into bars or squares.