- 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