Add the peanut butter and raisins to the bowl of a stand mixer. Using the paddle, mix for a few seconds to incorporate. Don't mix too long or you'll smash the raisins.
Spray a cake or loaf pan with cooking spray. Line with parchment paper and spray the parchment.
To cook the sugar to 245°F (hard ball stage), add the sugar and a splash of water to a nonstick pan. Cook on medium high until a thermometer reads 245°F. DO NOT STIR.
Immediately pour the sugar into the mixing bowl and mix on low for EXACTLY 30 secs. Pour the mixture into the prepared pan. Cool on a rack until room temp. or in the fridge.
When the halvah is hardened, drizzle the chocolate and peanuts on top. Refrigerate to set the chocolate and then slice.