Combine the dates, peanut butter, salt, lemon juice and vanilla extract in a food processor and blend till smooth.
Spread the mixture over the tray to a thickness of 1/2 inch.
Sprinkle over the buckwheat groats.
Pop the tray in the fridge for 2-3 hours.
Melt the chocolate in a heatproof bowl over a pan of simmering water making sure that the water is not touching the bottom of the bowl. Remove from the heat and allow to cool slightly.
Once the mixture in the freezer has hardened, chop into bars carefully. Aim for 5 - 6.
Dip the bars into the chocolate completely and refrigerate for 30 minutes.
Notes
These will keep covered in the fridge for up to 2 weeks.
The total time is without the time required to set the bars.