To make the swirl combine all the ingredients into a medium-size saucepan and cook over medium heat until rhubarb is tender and syrup forms; set aside to cool in the refrigerator.
In a small bowl whisk together the egg yolks, ¼ cup sugar, and the cornstarch; set aside.
In a large pot or saucepan (be sure to use a large enough pan for this the mixture will boil up pretty high)mix together the milk, cream, ¾ cup sugar, salt, and corn syrup. Bring the mixture to a boil over medium heat, reduce to simmer. Mix 1 cup of the milk mixture slowly into the egg mixture to temper the eggs, and then mix the egg mixture back into the milk and cream mixture to form the custard. Continue cooking on simmer stirring constantly with a wooden spoon until the custard thickens; remove from heat and stir in the vanilla. (custard is ready when you slide your finger across the spoon and the streak it makes stays in place).
Pour the custard into a food-grade zip lock bag and place it in a large bowl seam side up. Surround the bag with ice cubes and water – mostly ice cubes and let the mixture cool for 30 minutes.
Process custard in ice cream maker according to ice cream maker directions.
Layer the ice cream in a dish starting with the strawberry rhubarb sauce. (A 9×5 glass bread pan is just the right size for this)
Cover with plastic wrap and freeze for 3 – 4 more hours.
I have prepared this recipe as written and thought it was really good – but if I make this again I will use 1 teaspoon vanilla and 1 tablespoon of cornstarch in place of the amounts it calls for; I do believe that is a typo in the recipe.