Blueberry Cheesecake Bars

Gluten free lemon shortbread:

1. Adjust the oven rack to the middle position, pre-heat the oven to 350ºF (180ºC) and line a 9-inch (23cm) square baking pan with parchment/baking paper.
2. Tip: When lining the baking pan, I recommend leaving some parchment/baking paper overhang, as that will help with removing the bars from the pan later on.
3. Add the sugar and lemon zest to a large bowl, and use your fingertips to rub the zest into the sugar.
4. Tip: This helps to release more essential oils from the zest, and it will make your bars even more fragrant.
5. Add the softened butter and vanilla, and mix well with a wooden spoon or rubber spatula until combined.
6. Tip: Don’t cream or aerate the mixture, as that can make the shortbread too delicate and crumbly (note the absence of any raising agents for the same reason).
7. In a separate bowl, whisk together the gluten free flour blend, almond flour, xanthan gum and salt.
8. Add the dry ingredients to the butter-sugar mixture and mix well until it starts clumping together. Then, give it a knead until you get a homogeneous cookie dough.
9. Tip: Because it's gluten free, you don't need to worry about over-working the shortbread dough!
10. Press about ⅔ of the shortbread cookie dough (about 380g) into the lined baking pan. Smooth it out into an even layer, this is easiest done with a small offset spatula. Set the remaining ⅓ of the cookie dough aside until needed.
11. Bake the bottom shortbread crust at 350ºF (180ºC) for about 20 minutes or until evenly golden brown. Remove from the oven and allow to cool until warm while you prepare the cheesecake filling. Keep the oven at 350ºF (180ºC).

Cheesecake filling:

1. In a large bowl using a balloon whisk, mix the cream cheese and yoghurt together until smooth.
2. Tip: Make sure to MIX rather than whisk or aerate – you don't want to incorporate too much air into the mixture. If you don't want to do this by hand, use a stand mixer fitted with the paddle attachment on the lowest speed setting. (I don't recommend using a hand mixer.)
3. Mix together sugar and cornstarch (US)/cornflour (UK), and add them to the cream cheese mixture. Mix well until combined.
4. Add the eggs and vanilla, and mix well until smooth.

Assembling & baking the blueberry cheesecake bars:

1. Pour the cheesecake filling over the warm shortbread crust and smooth it out into an even layer.
2. Scatter the blueberries evenly over the cheesecake filling, then crumble the remaining ⅓ of the shortbread cookie dough on top, making sure that you get a fairly even coverage with some of the filling and blueberries peeking through.
3. Bake at 350ºF (180ºC) for about 40-45 minutes or until the crumble topping is golden brown and the filling is only very slightly wobbly when you shake the baking pan.
4. Tip: If the filling is too jiggly, it won’t set properly and could end up too soft (which will make cutting the bars a rather messy business).
5. Allow the bars to cool completely to room temperature in the baking pan and then chill them in the fridge for at least 2 hours. Once chilled, use the overhanging parchment/baking paper to remove them out of the pan, slice and serve. You can dust them with some powdered/icing sugar, if you wish.
6. The blueberry cheesecake bars will be even better after an overnight chill in the fridge.

Storage:

1. The gluten free blueberry cheesecake bars keep well in a closed container in the fridge for about 3-4 days.