Step 1 : Mix a little milk with the cornstarch, sugar and egg yolks, then bring the rest of the milk to the boil
Step 2 : Pour the milk over the egg mixture, whisking with a hand whisk, heat everything over low heat while whisking constantly until the cream sets.
Step 3 : Mash the banana with a fork, and sprinkle with lemon. Pour the cream over the bananas and mix, pour into glasses. Refrigerate the banana cream then serve chilled.