Preheat oven to 350℉ and lightly butter a 9"x9" baking pan. Line bottom and two sides with parchment, allowing a slight overhang.
In a medium sauce pan over medium heat combine dates, granulated sugar, orange juice and water. Allow to come to a simmer and cook uncovered for 8-10 until soft and jammy. Remove from heat and set aside.
In a large bowl combine oatmeal, flour, brown sugar, cardamom, baking soda and salt. Cut in butter using your fingers or pastry cutter until well combined and mixture holds together when lightly squeezed.
Evenly press a generous half of oat mixture (about 3 cups) into the bottom of prepared pan. Spread dates evenly over oats. Add remaining oat mixture, pressing slightly. Bake in preheated oven for approximately 30 minutes until golden. Remove from oven and allow to cool completely. Remove from pan by lifting the overhanging parchment and cut into desired squares.