1) In a large saucepan, add the milk, eggs, sugar, flour and lemon juice. Bring to a boil and reduce to a simmer, stirring constantly. Stir until the consistency of double cream and remove from the heat. Set aside to cool.
2) Once the lemon curd has cooled, divide it into two bowls. In a separate, small mixing bowl, whip the double cream until soft peaks form. Add the whipped cream to one of the bowls of lemon curd, gently folding it into the curd.
3) Using a pastry bag (or a large plastic bag with a hole snipped in one corner) inject the profiteroles with the lemon curd. Dip the profiteroles into the lemon curd and cream mixture, which has been set aside, to coat fully. Be sure to coat profiterole on all sides.
4) Place the profiteroles on a cooling rack so that the mixture settles. Let rest for 5 minutes.
Put the profiteroles on a serving plate and garnish with lemon zest.
Cook's note: If the lemon curd and cream mixture is too thick, add a little cream or milk. The result should be a sauce-like consistency.