Preheat the oven to 180°C and grease 6 tartlet tins or one big tart tin.
Heat the butter over medium heat and stir in the sugar to dissolve.
Add the olives and apple and cook slowly until caramelised.
Add the lemon juice and thyme and remove from the heat. Divide the mixture between the prepared small tins or turn into the large tin and leave to cool.
Cut out pastry rounds at least 1 cm bigger than the tin(s) and push down on top of the olive mixture.
Bake for 30 minutes or until the pastry is done and nicely puffed out.
Remove from the oven and leave to stand for a few minutes before turning out.
Bitter chocolate syrup Blend the cocoa powder and water in a saucepan.
Stir in the brown sugar, cayenne pepper, Worcester sauce and salt. Stir over low heat to combine, then boil to a syrupy consistency.
Drizzle over the tart before serving.