1. Add the salt, the flour, the caster sugar, the cinnamon, the vanilla extract and the butter in pieces to the work-bowl of the mixer.
2. Mix with the wire whip until our dough is formed, about 2-3 minutes. Since the biscuits have to be as crispy as possible, do not mix the dough for a long time, and this is why you use soft flour that does not contain much gluten.
3. Remove the dough from the work-bowl, now you can also shape it a little with your hands like a ball.
4. Wrap the dough with plastic wrap and put it in the refrigerator from 30 minutes to 1 hour until it becomes tight.
5. After one hour, preheat the oven to 190° C in fan mode.
6. Pour flour on counter, cut a piece of dough, and leave it on the counter.
7. Using a rolling pin, shape the dough in order to be 3 millimetres thick, if necessary sprinkle with a little more flour.
8. With a cookie mold cut biscuits in a diameter of 5-6 cm. If you do not have a cookie mold use a cup of tea or a glass to cut the dough.
9. Put the biscuits on two baking pans with baking paper, placing them close to each other.
10. Repeat for all the dough. There should be 24-30 biscuits.
11. Bake for 8-11 minutes. Biscuits should get a beautiful golden colour but do not expect them to be hard when you take them out of the oven.
12. Let them cool for 20 minutes from the time you took them out of the oven.

FOR THE FILLING

1. Add the butter to the work-bowl of the mixer and mix it with the wire whip for 1 minute in order to fluff.
2. Add the praline and mix for another 30 seconds until the filling is homogenized (do not mix it much to avoid curdling).

FOR THE ASSEMBLY

1. Put a small amount of the filling (1 tbsp) on a biscuit on the side on which it was placed in the oven.
2. Cover with another biscuit. Push a little for the filling to spread. If you want, decorate them with a little caster sugar.
3. Repeat for the rest of them.