In a large mixing bowl, add the flour and the sugar together
Divide the butter in small pieces and incorporate them in the mixture
Start mixing everything together with your hands and do not be afraid of getting them messy! (You can also start with a spatula)
After a few minutes of mixing, add the egg and keep mixing until you start obtaining a dough
Once the dough is formed, shape it as ball, gently press over it with the palm of your hand and cover it with cling film
Place it in the fridge for an hour
Now preheat your oven at 180 degrees Celsius (356 degrees Fahrenheit) with convection on, and your oven tray in the middle
Take the dough out of the fridge and using a pastry roll, start rolling it until you obtain roughly 3-4 mm in thickness
Using a round mold (or the edges of a bowl), do 12 to 16 spherical dough shapes, depending on the size you want
Then, using a much smaller cup, do a hole in the middle of 6 or 8 of them (6 if you did 12 or 8 if you did 16)
Place your newly formed disk shaped dough on a baking sheet over a baking tray and place them in the over for about 10 minutes, or until they turn golden
Next place them on a cooling tray for about 15 minutes
Now put 1 tsp of jam on each plain disk shaped baked dough and cover it with a center hollow one
Your jam sablés are ready to be eaten!