Shortbread Date Fingers

This recipe I picked up from a Brisbane news magazine and adjusted it to taste. I was happy to use dried dates, as they are a very cheap dried fruit with an exquisite taste. This bar turned out very tasty and I got lots of kudos for it. It's a bit of work with some prep but worth it in the end.
Prepare Base:
-Sift together 80 g (3/4 cup) caster or fine sugar, 1 1/2 cup white flour, 1/2 cup rice flour (or extra white flour if you don't have it) in a large bowl
-Add in about 1 cup of chopped butter and a tbsp of oil and mix until you get fine breadcrumb-like objects
-Add in 15ml cold water and 1 egg yolk
-Knead until it forms a dough and then freeze for 20 min or refrigerate for 1 hr
-After it's cool, roll it out to the size of your deep baking dish (mine was 12''/30 cm by 9''/24cm or something) and then refrigerate for another 20 minutes-Place on deep cooking tray lined with baking paper and bake in oven that's been preheated to 175C/350F for about 25 minutes or until it starts turning brown
Prepare Filling:
-While the base is baking, place about 400gm (almost 1lb, maybe 3 cups) of dried dates in a small pot
-Cover with water
-Add the zest of 1 orange, 1 tsp vanilla, 1 tsp cinnamon, and a splash of vegetable oil-Simmer for 15 minutes or until it turns to mushPrepare Topping:
-Mix 425 g or ~ 3 cups of self-raising flour with 2 cups caster sugar, 1 tsp cinnamon and 3/4 tsp of baking powder
-Mix in 1 1/2 cups unsalted chopped butter, with some oil, until coarse bread crumbs are formed
Cook:
-Spread the date-filling onto the base and sprinkle the topping crumbs over it
-Bake at 175C/350F for about 30 minutes or until it starts to get a bit golden on top. Check halfway and make sure it's firm - if not, sprinkle some more oil on top.
-Dust with powdered sugar on top and enjoy

Tips:
-This recipe called for a lot of butter. I used significantly less but substituted a fair amount of canola oil, olive oil and some egg white. It was from a pouring bottle and thus I do not know the exact amounts. Adding another egg or using applesauce and stuff would be a great way to cut out on the fattiness (though the fat is what makes shortbread short).
-The way I presented it was how I did it, but next time around I'd make the base and topping at the same time to cut down on time. Only for the end bit (mixing water and egg yolk) would I separate it. I'd also cut down on the sugar a bit as it was a tad sweet - otherwise, it was mighty tasty