Freeze the insulated bowl
Peel bananas and mash until smooth
Separate egg yolk from egg whites, place egg yolks in a large bowl
Beat egg yolks for a couple of minutes, stir in 1 cup sugar until smooth
Pour cream, milk, and vanilla into a saucepan, warm to a simmer but not a boil, stirring regularly
Take 1/4 cup of the warm milk and stir into eggs, stirring constantly - repeat with 1/4 cup at a time, stirring in, until half of the warm milk has been added to the eggs
Mix in the mashed bananas with the eggs and milk
Add eggs/milk/banana into the saucepan with the remaining milk
Stirring constantly and over medium low heat, warm the mixture until it reaches a temperature of 170 degrees, about 10 to 15 minutes
Remove from stovetop and pour into another bowl with lid, cool until steaming stops
Cover and place in fridge for miniumun of 1 hour and up to overnight
With all cold ingredients, add banana custard to ice cream maker following manufactor's instructions, until ice cream is thicken and creamy about a soft serve stage
Stop ice cream maker and remove mixing arm
Using a spatula add a section of the hardened blueberry spread to the ice cream, swirling in. Repeat until all blueberries are swirled in
Scoop into a frozen ice cream container, smooth, cover with plastic wrap against the top of the ice cream
If using a bread pan, cover with foil. If using an ice cream container cover with lid
Place in freezer and freeze ice cream for 2 to 4 hours before serving
Ice cream is best eaten day of preparation or 1 to 2 days after