Preheat the oven to 180°C/160° fan/350°F/gas mark 4. Grease a 5cm/2in deep, 20cm/8in round non-stick cake tin. It should NOT be loose bottomed or springform.
Stir together the melted vegan butter and the light brown soft sugar until smooth then spread it evenly across the bottom of the cake tin.
Thoroughly blot the pineapple rings and cherries dry with kitchen paper then arrange them in the base of the tin - one pineapple ring in the middle and six around the edge. You may need to squish them together a bit to fit them in. Place a cherry in the middle of each ring, and more in the gaps in between them if you like. Place the tin in the fridge while you prepare the cake batter.
In a large bowl, whisk together the plain flour, cornflour, sugar, baking powder, bicarbonate of soda and salt until well combined.
In a jug, whisk together the milk, pineapple juice, yogurt, oil, melted butter, vanilla and vinegar.
Pour the wet ingredients into the dry and stir with a balloon whisk until no dry lumps remain but do not over-beat the batter.
Pour the batter in to the pineapple lined cake tin and spread it level. Bake in the middle of the oven for about 50 minutes until the cake is firm to the touch and a skewer inserted into the centre comes out clean (don't push it all the way to the bottom though otherwise it may not come out clean even when the cake is cooked.).
Let the cake cool in the tin for 15 minutes then run a knife around the edge to loosen it, place a serving plate on top of the tin, carefully flip it over and lift off the cake tin.
Let the cake cool at room temperature for a couple of hours before serving.