These delicious berry meringue cookie bars are the perfect choice when you need a quick and easy dessert! With lemon zest in the dough and berry jam filling, it's the perfect balance of sweet and tangy.
Preheat fan oven to 160˚C (325˚F) or 175˚C (350˚F) if you're not using a fan oven.
In a bowl of a stand mixer, using a paddle attachment, beat butter, sugar and lemon zest until it combines and goes a little bit paler and fluffier, but not like when making a cake. (approx. 1-2 min) Add egg yolks, one by one, and beat until combined. Afterwards, mix in vanilla extract.
In a separate bowl sift together flour and baking powder. Add salt and whisk altogether. Add dry ingredients in two batches, beating just until everything combines and it forms a dough.
The dough will be sticky, that's fine. Try to roll the dough between two parchment papers to fit a 22x33 cm (9x13 inch) pan, keeping the dough on one of them for sticking reasons. If you find it hard or if it keeps tearing, don't worry, just patch everything using your hands. Using gloves might come in handy.
Bake the dough in a preheated oven for 15 minutes. While the dough is baking, prepare your fillings and toppings.
Depending on the jam you're using, heat it a little bit to make it spreadable. This way you're avoiding tearing the dough. When the dough is ready, cover it with layer of jam/preserve. It shouldn't be too thick, I usually use about 200 g of jam.
Clean the bowl of your stand mixer, as well as the whisk attachment, using a little bit of lemon juice or vinegar and a clean paper towel. This way we're eliminating traces of grease which could make making meringue impossible.
Combine the egg whites, sugar and a pinch of salt in a prepared bowl and put over a bain marie (a pot of simmering water). Stir constantly with a whisk to make sure the egg whites cook evenly. The mixture is done when it's hot and the sugar is completely dissolved. Rub a little bit of the mixture between your clean thumb and forefinger to test for graininess. If you can feel sugar granules, cook the egg whites some more. Ideally, the mixture should reach 70°C or 160°F. But if you don't have a thermometer, just make sure it's hot and smooth.
Wipe the bottom of the bowl, place it on your stand mixer and mix on high speed using a whisk attachment until you get stiff peak meringue and the sides of the bowl are cool to the touch. This could take anywhere from 5 to 15 minutes.
Spread meringue over the jam layer, sprinkle with hazelnuts and bake everything for approx. 30 min on 140˚C (300˚F) for a fan oven or 160˚C (325˚F) if not using a fan oven. The goal is to dry out the meringue, while not overbaking the dough.
When it's done, leave it to cool in the pan on a wire rack before cutting into it.
If you still don’t own one, I advise you to buy a kitchen scale – they’re cheap and easy to use, and always guarantee the same results in baking! :)