- 3/4 cup fresh blueberries
- 2 tablespoons granulated sugar
- 3 tablespoons, plus 1 teaspoon fresh lemon juice, divided
- 1 teaspoon cornstarch
- 1/2 teaspoon cold water
- 1 (14 ounce) can sweetened condensed milk
- Pinch of salt
- 2 cups chilled heavy cream
- yellow food coloring, optional
Place a loaf pan in the freezer to chill.
To make the blueberry sauce, combine blueberries, sugar, and 1 teaspoon of fresh lemon juice in a saucepan over medium heat. Stir and mash gently until the blueberries soften and release juices, about 5 minutes.
In a small bowl, whisk cornstarch and cold water together until smooth. Add this mixture to the blueberries, and bring the heat up to a boil.
Continue to cook and stir until the sauce has thickened, about 3 minutes. Then, remove from the stovetop, transfer to a heat proof bowl and cover with plastic wrap. Allow the blueberry sauce to cool in the fridge.
To make the lemon ice cream, combine sweetened condensed milk, salt, vanilla, and the remaining lemon juice in a medium-sized bowl. If using food coloring, add a few drops. Mix with a spatula until everything is smooth with no streaks.
In a large bowl, whip chilled heavy cream to stiff peaks. When the beaters are lifted, the peaks should be firm enough to stand without flipping over. Be careful not to overbeat the cream.
Pour about one cup of the whipped cream into the bowl with the condensed milk mixture. Stir and fold with a spatula until they are well combined. Then, pour that mixture into the large bowl with the remaining whipped cream. Again, use a spatula to stir everything until smooth with no streaks. The mixture will be very thick.
Begin layering the ice cream and blueberry sauce in the chilled loaf pan. Start with half of the ice cream mixture, then spread evenly with a spatula. Drop small dollops of blueberry sauce on top, and use a knife or toothpick to swirl the sauce with the ice cream. Pour the remaining half of the ice cream into the pan, add blueberry sauce, and swirl again.
Cover the pan with plastic wrap and place in the freezer. If you like a soft serve texture, freeze for 5-6 hours. For a more solid texture, leave to freeze overnight.