• Add butter and sweetener into a bowl. Using a spatula, mix everything together. Now add in egg yolk and vanilla extract. Continue mixing. Finally add in flour and bring everything together into a dough.
• Cover with cling film and chill in the fridge for 30 minutes or until it's manageable.
• Take a piece of dough and press it evenly into a 2.5 inch (6.5 cm) tart mould. Cut off excess dough with a knife. Using a fork, prick the base so that it doesn't puff up while baking. Repeat the same with the rest of the dough. Place them on a baking tray. Place them in the freezer for 10 minutes.
• Bake in a preheated oven at 340ºF (170ºC) , using upper and lower heat, on the lowest rack for 20 minutes. Remove from the oven and leave to cool completely. Once cooled, remove the shells from the moulds by flipping them and tapping a bit on the back of the back of the base to help releasing them. They're ready to be used!

Switch Them To Savoury Tarts

• Instead of 2 tablespoon sweetener, just add 1 teaspoon instead and ½ teaspoon salt together with butter. Omit the vanilla extract. Follow the same steps onwards for the rest of the recipe.