Measure and cut butter into chunks and place it into the freezer for a few minutes
Sift together dry ingredients; flour, icing sugar, almond, salt
Add very cold butter chunks into the dry ingredients, and rub the mixture between your hands until it becomes a sand-like consistency
Add egg into the mixture and mix with your hands just until the dough comes together
Knead the dough with the palm of your hand for a minute or two, just until the dough becomes smooth. Do not over-knead the dough and do not use mixer, neither a food processor
If the dough is too warm and sticky, place it into the fridge for 10-15 minutes first. Otherwise, continue with rolling the dough out into 2mm thickness between two Silicone baking mat. Place the dough into the freezer for 15 min in between the two Silicone baking mat. Do not remove the mat at this point Prepare your muffin pan or 12 mini tart molds
Take the dough sheet out from the freezer, remove the top of the silicone mat, and cut out circles, using a cookie cutter
With your fingers, press the dough circles into the tin one by one. Make sure that you work with a dough that is cold enough to be able to handle.
Once you are ready with all the tart shells, poke them with a fork, then freeze the dough for 1 hour before baking
Pre-heat oven to 180C / 356F (no fan) while the dough is in the freezer.
Bake for 15 min in the muffin pan. After 15 minutes the pastry cases will somewhat contract within the pan so you will be able to easily remove them
Once the tart cases are removed from the muffin pan to a baking sheet, bake for further 10-15 minutes at 160C / 320F (no fan). I suggest baking them in this second step upside down so the bottom of the tart case is up and can fully be baked until golden brown.
They are ready when they achieve an even golden color, in about 25-30 minutes overall