Add them into a pan with the sugar and heat on a medium heat.
Mash them slightly with a fork or spoon, and stir until the sugar has dissolved and the mixture has become quite saucy.
Blitz the mixture if you can with a blender, and pass through a sieve and discard the lumpy bits. If you can't blend it don't worry, just pass through a sieve anyway, you'll just get a bit less.
Leave to cool and refrigerate until needed.
For the Ice Cream
In a stand mixer, or a large bowl with an electric whisk, add the double cream and vanilla and whip until you get soft peaks.
Add in the condensed milk, and fold together to combine. Try not to be too rough otherwise it'll be runny and you want it to be thick still.
Spoon 1/3 of the mixture into your container/tin, and dollop on some coulis. Swirl through with a cake skewer/fork to get a ripple pattern.
Repeat again with the 2/3 of the mixture, and then the final third of mixture.
Freeze in the freezer for at least 4 hours, if not more.
To serve, take it out 10-15 minutes before being needed as it's firmer than shop brought ice cream as it has no additives.
Notes
You can use any flavour fruit if you want, but I wanted to make raspberry ripple. You could easily use strawberries, blackberries, blueberries etc! The coulis making process is the same.
I use a loaf tin to store mine in, but any Tupperware container that can fit the mix will do!
I serve mine in cones, with an extra coulis drizzle, and some freeze dried raspberries!
It's also great serve in an ice cream bowl, or even made into a milkshake.
This will last in the freezer for up to 3 months, but ideally eaten within a month.