Combine the dates, tiger nuts, carob powder, water, and collagen in the food processor. Blend until smooth. Lightly grease an 8x8 baking dish with coconut oil. Press the bar mixture into the dish with your fingers until it's evenly distributed. In a medium bowl, combine the carob, maple syrup, and coconut oil. Stir until a paste forms. Spread over the bar mixture until it's smoothed evenly. Pop in the fridge for at least two hours to set. Cut into squares. Store in the fridge for 1 week or in the freezer for 2 months.