Prep: Preheat oven to 375℉. Line a 9x13 baking pan with parchment, ensuring their flap folded over the sides for easy removal. Spray bottom of pan with olive oil or your favorite non-stick cooking spray.
Crust Dry Ingredients: In a large bowl, whisk together 2 ¾ cups all-purpose flour, 1/2 cup brown sugar, ½ cup organic cane sugar, ¼ cup rolled oats, 1 tablespoon ground flax, and pinch kosher salt. Set aside.
Crust Wet Ingredients: In a separate small bowl, whisk together 1 egg and 1 teaspoon vanilla extract. Pour into flour mixture and stir to combine. Add 1 cup salted butter (room temperature) to flour mixture and cut into flour with a fork.
Baking Dish: Pour a little more than half of the flour mixture into the prepared baking pan. Spread out evenly and press down firmly with your hands to create the crust. Set aside.
Make Filling: In a medium bowl, combine ½ cup organic cane sugar and 1 tablespoon cornstarch. Add 1 tablespoon orange juice, 2-3 teaspoons orange zest½ teaspoon vanilla extract and ⅛ teaspoon ground nutmeg. Stir to combine. Add 4 cups fresh cranberries and gently combine. Pour cranberries on the crust and spread out evenly.
Topping: Add 3 tablespoons brown sugar to the remaining flour mixture. Use a fork to combine. Crumble the mixture evenly over the top of the cranberries.
Bake: Place in the oven, middle rack, 40-45 minutes or until the top starts to become golden brown.
Serve: Remove and let cool completely before cutting into squares.
Notes
Brown Sugar: you can use coconut sugar in place of brown sugar, if you prefer, it will be a bit less sweet.
Gluten-Free: to make this gluten-free use 1-to-1 gluten-free flour and gluten-free rolled oats.
Dairy-Free: to make this dairy-free use a plant-based butter.
Storage: Store covered in the refrigerator for up to 5 days.