Prepare an 8x8 pan with parchment paper, leaving parchment to hang over the edge a bit for easy removal.

Bring a pan of water to a boil.

Place butter, morsels, sweetened condensed milk and vanilla in a glass bowl that will fit snugly on the pan of water.

Place glass bowl on top of pan with boiling water. Turn down heat to medium/low. Stir over heat until ingredients are well combined and smooth.

Spread mixture into prepared 8x8 pan.

Drop the sun butter by spoonfuls all over the top of the chocolate mixture.

Swirl in the sun butter by dragging a butter knife through the sun butter.

Refrigerate at least 2 hours to set.

After fudge has set, remove from pan, lifting with parchment overhang. Cut into squares.

Enjoy!