• Butter an 8x8 pan (or line with non-stick foil or parchment).

To make the fudge:

• Whisk together sugar, cocoa, peanut butter powder and salt in a medium to large saucepan.
  2 cup sugar, ¼ cup cocoa powder, 1 tablespoon peanut butter powder, ¼ teaspoon salt
• Add cream and milk a little at a time, stirring to make a paste.
  ½ cup milk, ½ cup cream
• Add the corn syrup and butter.
  3 tablespoon butter, 1 tablespoon corn syrup
• Place over medium heat and stir with a wooden spoon (or thermometer spatula) until boiling.
• Continue to cook, stirring frequently, until soft ball stage (235° - 240° F).
• Remove the pan from the heat, add the peanut butter and vanilla; stir vigorously until creamy. The gloss and color of the mixture will change, becoming lighter and more matte just before it is creamy. The temperature will drop significantly (by about 60°), but the mixture should still be pourable.
  1 teaspoon vanilla, 2 tablespoon peanut butter
• Pour into the prepared pan (spread to corners if necessary).

To make the drizzle:

• Melt the peanut butter in a small microwave safe bowl, stir in the powdered sugar until smooth. Drizzle over the surface of the fudge.
  2 tablespoon peanut butter, 1 tablespoon powdered sugar
• Drizzle over the surface of the partially set fudge.
• Do not cool completely before cutting; the fudge should still be warm and slightly soft when you cut it into squares (~1 inch). Let it cool completely before storing in an air tight container.