Lemon & Mascarpone Ice Cream

Ingredients
4 Egg Yolks
4oz/100g Sugar
10oz/300ml Milk
10oz/300ml Heavy Cream
8oz Mascarpone at room temp
Zest of 1 Lemon
Method
Pour Milk into saucepan & slowly heat until almost boiling, then remove from the heat. Do not let it boil.
Mix together the sugar & the egg yolks. Add the hot milk really slowly, so the eggs don't scramble. I usually just put a splash of milk into the bowl in the beginning.
Return to the mixture to the pan. Stir constantly while gently heating until it has thickened enough so a film forms on the back of a wooden spoon that you can run your finger through & it leaves the line. Do not let it boil or it will separate. Remove from heat.
Wait 5-10 minutes, but mixture is still warm, add the Mascarpone & stir until it melts. Let cool.
Add Lemon Zest to Mixture & put in fridge.
Once cold, add Heavy Cream & stir well.
Turn on ice cream maker & pour in mixture. As ice cream begins to form (3-4 minutes) add an egg white.
When Ice Cream has become solid & bowl rotates around ice cream (about 15 mins total), transfer to a freezer safe container, cover & let freeze until set. I generally wait 4-6 hours, or overnight.