Put the flour in a bowl together with the diced and very cold butter. We work the pieces of butter with the tips of our fingers, constantly crushing them together with the flour until we get an earthy texture without pieces of butter, then we put the 125 grams of water and we begin to knead first inside the bowl a couple of minutes and another two minutes on the countertop.
Return the dough to the bowl lightly smeared with sunflower oilCover with a cloth and leave to rest in the fridge for 1 hour. We put a little flour on the counter so that the dough does not stick when working it, stretch the dough in the shape of a rectangle.
We paint the entire rectangle with melted butter and a brush. Sprinkle the rectangle with a thin layer of cornstarch with the help of a strainer. Roll the rectangular dough on itself completely until you have a cylindrical-shaped roll.
Wrap tightly with cling film and let stand 30 minutes. After 30 minutes we repeat the operation, stretch in a rectangular shape, paint, sprinkle, roll up, film and put in the fridge (the third stretched and rolled is optional, with two vouchers).
We stretch the dough with a thickness of 1 centimeter and cut it into squares of 10×10 centimeters we will use 2 squares for each cupcake. To form a cupcake we put a square of dough, paint its entire surface with water, we put in the center a cube of sweet quince or sweet potato approximately 2×2 centimeters.
We cover that square with the candy in the middle with another square rotated 90º, in such a way that seen from above we have an 8-pointed star. We press the top dough well against the bottom right on the sides where the sweet is so that it is well encapsulated and without air.
Fry at 140º for 2 minutes on each side, moving constantly so that the ends begin to grow. We remove and reserve until we have fried all. We raise the oil to 180º and finish frying the cupcakes until they are completely golden.
We take out to a grid upside down to drain all the oil. With the 100 grams of water and 100 grams of sugar, we make a syrup by boiling the whole for 5 minutes that once cold we will put on top of the cake to finish them.