In small cup add 1/4 cup milk and 1 teaspoon corn flour. Mix very well without any lumps. Set aside.
Take the remaining milk in a thick bottomed pan. Add sugar and mix well. Start heating in medium flame. Stir well and cook till the sugar is dissolved completely. Now add the corn flour slurry and mix well. Cook in low flame until the custard thickens and coats the back of the ladle. Keep mixing and stirring to avoid lumps. Once the custard is ready transfer to a bowl and chill for 3-4 hours.
Take fresh cream in a clean bowl and beat for few minutes. Add vanilla, icing sugar and beat till soft peaks are formed.
Fold the prepared custard to the whipped cream and mix very gently. The cream should not become flat and loose its peaks while folding. Once done transfer to a freezer safe container and freeze for 4 hours. You may beat the semi frozen mixture again to break any ice crystals but there will not be any crystals in this method. Freeze the ice cream for8-12 hours. Scoop and serve vanilla ice cream as needed.
1. Do not add more corn flour as the custard will turn pasty. 2. You can add desired topping while serving