For the cream: zest and juice the lemon, keeping the juice and the zest separate from one another.
Whisk the egg yolks, sugar and corn starch together. Add the lemon zest and stir. Bring the milk to boil and then pour it over the egg mixture. Whisk to incorporate. Return the mixture to the heat and stir until the mixture starts to thicken. Remove from the heat, add the lemon juice and stir until the mixture is smooth and glossy. Cool the crème patissière and then transfer to a piping bag.
For the fruits: cut the strawberries into quarters, removing the stalks. Wash the plums and cut the plums into thin wedges, discarding the stones.
To assemble: fill the pastry cases with lemon crème patissière, carefully arrange the strawberries, plums and blueberries on top and then drizzle the maple syrup over the fruit. Serve immediately.
«Vary the fruits in this tart according to season - the lemon cream works very well with fresh raspberries.»