Once the mixture is hot but not boiling, pour in the cornstarch slurry. Bring to a gentle simmer while stirring constantly, and cook for 1 minute until the mixture thickens slightly.

Remove the pan from the heat. Let the mixture infuse with the vanilla pod still in it for at least 1 hour. Then strain, cover with plastic wrap (pressed directly onto the surface), and chill completely in the fridge.

Put the blueberries into a smaller saucepan, then add the honey, cane sugar, thyme, freshly grated lemon zest, and freshly squeezed lemon juice.

Place the pan over low heat. Bring to a simmer, stirring occasionally, and let it bubble gently until the liquid partially evaporates and the compote thickens to a syrupy consistency. This should take about 10-15 minutes.

Remove the thickened blueberry compote from the heat and let it cool completely. Once cooled, you can blend it briefly for a smoother ice cream texture, if you like.

Pour the fully chilled vanilla base into your prepared ice cream maker. Churn according to the manufacturer's instructions until it reaches a soft, scoopable consistency.

Layer the vanilla ice cream first, then the blueberries, then another layer of vanilla ice cream. Run a spoon through in a zigzag motion to create a marbled effect. Seal the container and freeze for a few more hours until firm.