Make the berry compote: In a small saucepan, add the berries, sugar or honey, and lemon juice. Cook over medium heat for 5–8 minutes, stirring occasionally, until the berries break down and the mixture thickens slightly.
Mash gently with a spoon. Taste and adjust sweetness or lemon as needed. Set aside.
Heat the milk: In a separate medium saucepan, add the milk and optional cream.
Warm over medium-low heat until steaming, not boiling. Keep the heat gentle to avoid scorching.
Add white chocolate: Remove the milk from heat. Add the white chocolate and a pinch of salt.
Let it sit for 30 seconds, then whisk until smooth and fully melted. Stir in the vanilla.
Combine: Spoon a swirl of berry compote into each mug. Pour in the hot white chocolate.
Add another spoonful of compote on top and gently stir to create a marbled look.
Garnish and serve: Top with whipped cream, a few fresh or thawed berries, and a light dusting of cinnamon or cardamom if you like. Serve warm.
Make it for a crowd: Double the recipe and keep the white hot chocolate warm in a slow cooker on “warm.” Add the compote per mug to keep the swirl bright and fresh.