¼cupunsweetened medium coconut,for crumble topping
In a medium saucepan, combine sugar, cornstarch and lemon zest. Add lemon juice and cranberries. Stir to combine. Heat to boiling, then reduce heat to low and simmer for 15 minutes until mixture begins to thicken.
Preheat oven to 350°F. Line an 8-inch square pan with parchment paper.
Add melted butter to a medium bowl (or melt it in the bowl in the microwave). Stir in sugars and vanilla, then add flour and oats.
Set aside 1 cup of the oatmeal mixture for the topping. Transfer the remaining amount to the prepared pan, pressing it evenly into the bottom to create a firm base.
Spread the cranberry mixture on top of the base, taking care to leave a ½ inch margin to prevent the cranberry from leaking out the edges while baking.
Add ¼ cup coconut to the remaining 1 cup oatmeal mixture. Sprinkle the topping evenly over the cranberry layer. Bake for 30 - 35 minutes or until golden brown. Cool completely before cutting into bars.