You will need:
4 cups (950 ml) milk
1 1/4 cups (250 g) sugar
2/3 cup (80 g) flour
1/8 tsp (1 ml) salt
1 (14 ounce) can sweetened condensed milk
2 tbs (30 ml) vanilla extract
In a large heavy saucepan, bring milk to a boil.
Combine the sugar, flour, salt and eggs in a seperate bowl.
Slowly add half of hot milk to the sugar, flour and egg mixture. Then return it all back to the saucepan. You will see lumps form. That is perfectly OK, just keep stirring they will smooth out. Watch the heat if you start to see tiny brown flecks that means the bottom is browning, reduce the heat.
Cook and stir until mixture reached at least 160 degrees F (71 degrees C) and coats the back of a metal spoon. It somewhat resembles thin vanilla pudding.