Heat the oven to 200C/fan 180C/gas 6. Roll out the pastry large enough to cut out 6 × 15cm circles. Sprinkle some chilli flakes in 6 × 10cm tartlet or Yorkshire pudding tins (if you only have loose-bottomed tins, line them with a circle of parchment paper that comes up the sides, to stop them leaking). Then divide the shallot mixture between them and lay a circle of pastry on top of each, tucking any excess down the sides around the shallots. Bake for 20-25 minutes, until the pastry has risen and turned golden. Invert the tarts onto serving plates and put a slice of blue cheese on top of each one to melt.