In a medium saucepan, combine the heavy cream and coconut milk over medium-high heat. Stir in the granular sugar substitute while heating until bubbles form around the edges, about 5–7 minutes.

In a medium bowl, whisk the egg yolks until they become light and frothy, about 2 minutes. Gradually pour the warm cream mixture over the yolks, whisking continuously.

Return the tempered mixture to the saucepan over low heat and add the sugar-free white chocolate chips. Stir constantly until melted and smooth, about 3–5 minutes.

Transfer the mixture to a bowl to cool slightly, then cover and chill in the refrigerator for at least 4 hours.

In a small saucepan, combine the frozen raspberries with a sweetener over medium heat and cook until they break down into a jam-like consistency, about 5–7 minutes.

Once the ice cream base is chilled, pour it into an ice cream maker and churn according to the manufacturer’s instructions, about 20–25 minutes.

In a freezer-safe container, scoop half of the churned ice cream, drizzle in spoonfuls of the raspberry swirl, then add remaining ice cream and swirl gently.

Cover the container and place it in the freezer overnight or for at least 6 hours until firm.