Using the Pineapple cutter PROFESSIONAL PLUS slice the pineapple into slices and pieces.
To make the thyme syrup, bring water to a boil, then add sugar and thyme. Let it simmer gently while stirring until the syrup becomes clear. Let it cool and remove the thyme.
Preheat the oven to 180°C (356°F) with both top and bottom heat. Mix butter, sugar, and a pinch of salt with the dough hooks of a hand mixer. Incorporate the egg briefly, then add the flour and 2 tablespoons of cold water. Knead the mixture first with the dough hooks, then with your hands until you have a smooth dough. Wrap it in plastic wrap and refrigerate for 1 hour.
Line a 24 cm (9.5 inch) tart pan with a removable bottom with parchment paper. Roll out the dough between two sheets of plastic wrap using the ROLLING PIN EXACT (exact dough roller) and line the tart pan with it. Place parchment paper and dried beans on top of the dough and bake for about 15 minutes.
For the filling, mix mascarpone, crème fraîche, egg, cornstarch, lemon zest, sugar, and vanilla bean seeds. Distribute the pineapple pieces on the crust, pour the filling over them, and bake for another 20-30 minutes until done.
To serve, top the tart with pineapple slices, drizzle the syrup over it, and garnish with thyme leaves. Optionally, dust with powdered sugar.