Step 1: Line a rectangular baking mold or an 8×8 inch pan with parchment paper, leaving an overhang for easy removal of the tombstone chocolate bars.
Step 2: Melt the dark or milk chocolate using a double boiler or in 30-second intervals in the microwave, stirring until completely smooth.
Step 3: Pour the melted chocolate into the prepared pan and spread it evenly with a spatula to create the base for your tombstone chocolate bars.
Step 4: Tap the pan firmly against the counter to remove air bubbles. Sprinkle the crushed cookies over the top to represent the graveyard soil for the tombstone chocolate bars.
Step 5: Let the chocolate set at room temperature for about 15-20 minutes until it is firm enough to hold weight but still soft enough to insert items.
Step 6: Gently press the 12 oval cookies or chocolate rectangles into the base, spacing them out so you can later cut the area into 12 individual tombstone chocolate bars.
Step 7: Melt the white chocolate chips with the coconut oil. Transfer to a small piping bag with a fine tip and pipe ‘R.I.P.’ or cross designs onto each ‘tombstone’ piece.
Step 8: Allow the tombstone chocolate bars to set completely (about 2 hours) before slicing them into individual rectangular bars and serving.