Mix the egg yolks and sugar together in a bowl and set aside.
Pour milk, cream and extract in a saucepan and heat until just beginning to boil.
Add approximately 1 cup of the milk mixture to the egg and sugar mixture and stir well.
Add this mixture back into the saucepan with the rest of the milk mixture and stir well.
Heat until the mixture reaches 175-180F.
Strain through a sieve, cover and chill for at least 2 hours, or overnight.
Pour into ice cream maker and follow manufacturer's instructions for churning. Add the crushed mints into the ice cream maker during the last 1-2 minutes of churning.