Step 1
Preheat the oven to 180°C/fan oven 160°C/ Gas Mark 4. Lightly grease a round 23cm (9in) shallow cake tin with a little Trex.
Step 2
Spoon the syrup into the cake tin, spreading it over the base. Place a cherry in the centre and arrange the pear halves, cut side down, in a fan around the central cherry. Place the other glace cherries among the pears.
Step 3
Sift the flour, cocoa powder and salt into a mixing bowl. Add the sugar, Trex, unbeaten eggs and vanilla extract. Use a wooden spoon to beat the mixture together until smooth and creamy – this will only take 1-2 minutes.
Step 4
Spoon the mixture into the cake tin and spread it out carefully to cover the fruit. Transfer to the oven and bake for 35-40 minutes.
Step 5
Cool the cake in the tin for 10 minutes, then run a knife around the edge to loosen the edges. Place a large plate on top of the tin, invert quickly and lift the tin away. Cool completely.