Into a mixing bowl, add the Butter (250 gram), Powdered Confectioners Sugar (2/3 cup), and Vanilla Extract (1 teaspoon). Pulse everything together with an electric mixer. Then add and mix the All-Purpose Flour (2 cup), and Custard Powder (1/3 cup).
Take tablespoons of the dough, roll them in your hands and place them onto a baking tray lined with some baking paper. Bake inside a preheated oven, 160 degrees C (325 degrees F) for about 15 minutes.
To make the filling, mix together the Cream Cheese (100 gram), Powdered Confectioners Sugar (1 cup), and Lemon Juice (2 tablespoon).
Take one cookie, rub it with the filling, and top it with another cookie as a sandwich.