Wash the quinces and clean them with fluff, then wipe them well with a clean towel, slice and clean the shells and stalks.
In the form for countertops, or in a special pan for this purpose (I use a special pan only for countertops, which fits perfectly with the cake stand) put sliced butter on the entire surface and pour the sugar on top. to level the base. Knowing that the quinces are a little sour, I used 250 grams of caster sugar.
The quince slices are placed radially, in a circle, around the shape of the cake, and the quince pieces are placed in the middle and between the slices. Sprinkle 2-3 tablespoons of caster sugar over the quince, then put the pan in the oven over medium heat until the butter melts, the sugar dissolves and the quince slices soften.
When the quinces have softened and the sugar has dissolved, remove the pan from the oven and leave to cool and turn off the oven.
Meanwhile, prepare the composition for the countertop. Separate the egg whites from the yolks and mix, incorporating one by one, little by little, the sugar, vanilla, the yolks, the flour and finally the oil.
The resulting composition is poured into the pan / form over the cooled quinces, leveled and put in the oven, about 30-35 minutes, over medium heat, until the top grows and browns nicely. Then remove the pan / form from the oven and leave to cool for 7-8 minutes.
Prepare a bound (but not hard!) Syrup from 4 tablespoons of caster sugar and 6 tablespoons of water. When the syrup is lightly bound, leave to cool slightly and then add a few drops of lemon essence (or lemon juice).
When the syrup has cooled a little, pour it over the cake, distributing it evenly over the entire surface (and especially on the edges), leave it for 3-4 minutes, then quickly and safely turn it over in the tray or cake holder.
It can be decorated with cream, grated or melted chocolate, decorative ornaments, jam ...