Grease a 13x9-inch pan, and line with foil or parchment paper.
Combine brown sugar, flour, baking soda, salt, and rolled oats. Cut in butter with a pastry blender or two knives until mixture is crumbly.
Press 2/3 of the crust mixture into the prepared pan. Slice the guava paste into enough pieces to cover the crust within 1/4 inch of the edge, and place in pan. Sprinkle remaining crust mixture over guava paste layer.
We instantly fell in love with the adorable Reindeer Gingerbread Cookies we found at TheSweetChick.com. Carole's recipe became our inspiration for our next Pinterest Test Kitchen Challenge. What You'll NeedYour...