Put the milk, sugar, and salt into a medium mixing bowl. Whisk well until the sugar is dissolved.
Stir in the heavy cream and vanilla. Cover and refrigerate at least 2 hours, preferably overnight.
Turn on the Cuisinart® ice cream maker.
Whisk the ice cream base, and then pour the mixture into the freezer bowl through the ingredient funnel.
Churn until thickened, 15 to 20 minutes.
Gradually add the strawberry jam and cubed doughnuts through the ingredient funnel a minute or two before the end of churning time.
The ice cream will have a soft, creamy texture. For a firmer consistency, transfer the ice cream to an airtight container and place in the freezer for about 2 hours.
Remove from the freezer about 15 minutes before serving.