First prepare the dough by mixing flour, water and salt in a bowl. Knead until it becomes elastic and comes off the hands. Let it rest for 10 minutes.
We flour the worktop and spread a sheet with a thickness of 0.5 cm, no more, because the martyrs swell when boiled and it is not preferable to become too thick, then sprinkle again with flour over the sheet, so that when we cut with the appliance, the shell to come off easily. We place them in the tray next to each other.
From the above quantity, two trays 23x33 cm came out.
We leave the martyrs to dry until the next day, or if we hurry, we put them in the hot oven for 15 minutes, over medium heat.
To obtain the syrup, we put water with salt on the fire and when it starts to boil we add the martyrs. Let them boil until they rise to the surface and add the sugar, letting it melt, then turn off the heat. When they are close to room temperature, add lemon juice and peel, rum and vanilla essences.
When serving, add crushed walnuts and cinnamon to taste.