Place the white chocolate in a large bowl and set a fine-mesh sieve over top of the bowl. Set aside.
Combine the milk, sugar and salt in a medium saucepan and stir over medium-low heat until the sugar dissolves. Allow to cool for about 10 minutes.
In a separate heat-proof bowl, whisk the egg yolks for about 2 minutes on high or until they are pale and fluffy. Slowly pour the milk mixture into the egg yolks, whisking constantly to prevent curdling then scrape the mixture back into the saucepan.
Warm the mixture over medium heat, stirring constantly with a rubber spatula until the custard thickens just enough to coat the back of the spatula. It should steam but not boil and will take around 5 minutes.
Pour the custard through the strainer onto the white chocolate. Stir the mixture for about 2 minutes or until the chocolate has completely melted. Allow the mixture to sit for about 10 minutes.
Stir in the heavy cream, mascarpone and vanilla bean paste and mix well to combine. Cover and chill in the refrigerator at least an hour - it will be quite thick - then pour into silicone cupcake forms. Place the cupcake forms on a tray and freeze for 3 hours or overnight.
For the raspberry sauce
Defrost the raspberries if using frozen ones. Combine the raspberries, sugar and vodka in a small saucepan. Mash with a fork until juices are released but large chunks still remain. Cook over medium-low heat until the sugar dissolves and the sauce is heated through (about 5 minutes).
Remove from the heat and allow the sauce to cool to room temperature. Cover the bowl with plastic wrap and refrigerate until chilled (at least 45 minutes).
To serve
Remove the frozen panna cotta from the freezer and free them from their silicone forms and place on a plate. If they are not releasing from their form easily, hold them briefly under hot running water, silicone side up.
Spoon over some of the raspberry sauce and serve with fresh raspberries.
Notes
For a subtle taste difference, use vanilla vodka instead of normal vodka. If you are serving children, you might want to use water instead of vodka.If you don't have vanilla bean paste, use vanilla extract.If you prefer not to serve the ice cream as individual "panna cotta", cover the mixture with plastic wrap and cool it in the refrigerator, preferably overnight, before freezing in your ice cream maker following the manufacturer's instructions.