Spread filtered flour on a working surface and mix in the ground almonds and sugar. Make a well in the center, add the egg to the well and put the cold butter in small pieces around the edge. Mix everything together, then quickly knead it with your hands until smooth. Wrap with foil and let cool for about 1 hour.
Roll the dough around on a floured surface and line the greased tin with it, forming a crust around the edge. Pierce with a fork several times.
Place the dish on the middle rack of the preheated oven (200°C, approximately 400°F) and bake until golden brown, or for about 10 minutes. Remove from the oven, then let cool slightly in the tin.
For the filling: melt the butter in a saucepan over low heat and add the remaining ingredients, stirring constantly. Stir until the cream thickens and blisters. Don't let it get frothy.
Loosen the crust from the mold and add the filling. Let cool.
For the raspberry sauce: rinse the berries (setting some aside for garnish). Mix the berries with the powdered sugar and sherry, then bring to a boil and let simmer for a few minutes. Strain through a sieve and let cool.
To serve, pour some strawberry sauce over the tart and decorate with fresh raspberries.