These Gluten-free Lemon Cookies are crispy, buttery, shortbread-like cookies with a delicious tangy lemon flavor that is coming from freshly squeezed lemon juice and freshly grated lemon zest. They are absolutely delicious on their own, but turning them into blueberry jam filled cookie sandwiches is like a match made in heaven.
Pre-heat oven on 390 Fahrenheit (200 degrees Celsius).
Add all ingredients (rice flour, buckwheat flour, lemon juice, lemon zest, corn starch, sugar, butter, salt) to a food processor and pulse until you get a crumb-like texture. (It will not likely form a ball yet.)
Take a mixing bowl and add the dough from the food processor. Knead it with your hands for 2 minutes or so to form a ball. If the ball is dry and crumble still after 2-3 minutes, add 1-3 tsp water, 1 tsp at a time.
Take your rolling mat and lightly flour it. I use rice flour as its grainy texture helps with the rolling. I also use a saran wrap/cling foil on the top so the dough will not stick to the rolling pin.
Roll the dough thin 4 mm (approx. ¼-inch). Choose your favorite cookie cutter and cut out the shapes you want.
Bake them on parchment paper for 10-12 minutes. Baking time may depend on your oven, so check them around 8-10 minutes.
How to add the jam filling?
If you want to fill the cookies with jam, make sure you cut and bake the cookies in pairs. One full cookie and one with a "window".
Once the cookies have cooled down, spread a bit of jam on a full cookie and place the "window" cookie on top. Gently press it together to make a lemon cookie sandwich.
Measure it with a scale - Baking is about precision. To bake something perfectly is a question of science like how different ingredients react to each other under heat. I always measure the ingredients as well on a scale and convert the recipe back to cups. I use King Arthur's Weight Chart to make sure that the cup measurements are in-line with the grams. If you want to make these cookies perfectly ever time, make sure your measurements are precise.
Flour your surface - I like using rice flour to dust my rolling mat. Rice flour seems to have a non-stick tiny ball-like consistency that just makes working with any dough easier.
Parchment paper instead of a baking sheet - I recommend using parchment paper instead of a baking sheet especially if you are making multiple batches. You can take out the parchment paper from the sheet pan and bake the next round, while the first round can cool down on its own. If you try to move them while they are hot, they will likely break.
Place them close - As there is no baking powder, baking soda or any other type of leavening, they will not rise significantly. You can place them relatively close to each other.
When are they ready? - If they start to brown on the edges, you are too late.