Heat until just melted, stirring constantly. Once the mixture comes together and the oil has melted, immediately remove from the heat.
Stir in the cocoa and salt, mixing to combine.
25 grams (¼ cup) cocoa powder, ¼ teaspoon sea salt
Add the puffed wheat and stir, using a spatula, until fully coated in the peanut butter mixture.
6 cups puffed wheat
Turn the puffed wheat mixture out into the prepared baking dish and press into as even a layer as possible.
Place the dish into the freezer and chill for at least ten minutes (or refrigerate for 30 minutes), then lift it out of the dish with the parchment paper and slice into bars.
Store the bars in an airtight container at room temperature for a couple of days, or freeze up to three months. I prefer to keep these in the refrigerator for best texture.
Notes
Update 12th May 2025: after receiving some comments about the weight being incorrect, I bought every kind of puffed wheat I could get my hands on and asking a colleague in Canada to do the same. We've concluded that there's a real variation in terms of weight between different types and brands (e.g. khorasan puffed wheat vs. standard) and as a result I have removed the weight measurement from the puffed wheat for this recipe. This is one of the only times that cups are more accurate!To ensure that the bars stick together properly, use natural peanut butter from a freshly opened jar, not the dry bits at the bottom. It works best if the dates are very soft but they can be soaked if necessary.If using the cup measurements, be sure to do the heaping measurement for peanut butter and really pack it with the dates. If you didn't omit or reduce any ingredients and your bars still aren't sticking together, add a little more peanut butter and/or honey.Be sure to use natural peanut butter with no added ingredients (other than salt). I haven't tested this with sweetened peanut butter but I think it probably wouldn't work.* In the step-by-step images, you'll see that it's a rectangular dish. That's because the recipe as shot there was doubled, but it was too much for a single batch - it's been reduced now for a more manageable amount.