1. In a medium saucepan, warm the milk with the sugar and mint leaves. Remove the saucepan from heat, cover, and steep for 30 mins.
2. Meanwhile, prepare an ice bath using two bowls, one larger than the other, and have a strainer handy. Fill the larger bowl halfway with ice and water. In the smaller bowl (it should hold at least 2 quarts) add the chopped white chocolate.
3. Place the egg yolks in a medium bowl. Rewarm the milk, the gradually whisk it into the egg yolks. Pour the mixture back into the saucepan and cook over medium-low heat, stirring and scarping the botttom constantly with a heatproof spatula until the custard is thick enough to leave a trail when you draw your finger through it, about 3 to 5 mins.
4. Strain the custard over the white chocolate and stir until the chocolate is melted. Cool the creme anglaise completely over the ice bath, stirring occasionally. Refrigerate until ready to serve.