Procedures

1. 1

   In a blender, combine half and half, peanut butter, 3/4 cup sugar, 1/2 teaspoon salt, and vanilla. Blend until smooth, then transfer to an airtight container and chill for 3 hours or until very cold.

2. 2

   Churn ice cream according to manufacturer's instructions.

3. 3

   While ice cream is churning, heat 1/2 cup sugar with just enough water to moisten in a heavy saucepan. Cook on high heat until sugar melts and caramelizes, rotating pan to correct for hot spots on burner. When sugar turns a dark amber and smells slightly smoky, quickly stir in butter until fully incorporated, then remaining salt and cream. Caramel will bubble up and steam. When caramel is cool enough to taste, add more salt if desired.

4. 4

   Transfer ice cream to a very large mixing bowl, and quickly fold chocolate and peanuts with a large spatula. Then pour warm caramel sauce into ice cream, folding quickly and constantly with spatula to distribute caramel into an even, thread-like swirl. (Having a friend on hand to pour caramel while folding in makes the job much easier.) Transfer ice cream to freezer in an airtight container to firm up for several hours before serving.