Grease an 8x8 or 9x9-inch glass baking dish with oil or butter and line with unbleached parchment paper.

Place peanuts and dates in the bowl of a food processor and process until completely crumb-like and sticky. Press into the bottom of your baking dish evenly, creating a crust. If mixture is too sticky, use plastic wrap to help spread it out.

Using a double boiler or glass bowl over a saucepan of simmering water, melt chocolate with 2 Tablespoons of peanut butter and stir until combined and creamy. Pour on top of the peanut/date crust.

Using a small spoon, drizzle (do NOT dollop) the remaining 2 Tablespoons peanut butter over the chocolate, teaspoon by teaspoon, in lines. If your peanut butter is not loose enough to do this, warm over a double boiler to thin it out.

Using the tip of a knife, gently create swirls along the top of the bars. Refrigerate for 2 hours. Remove from refrigerator 10 minutes before serving. Remove from baking dish and cut into squares. Serve immediately or keep in the fridge.