Line a loaf tin or square baking tin (approximately 20cm x 20cm) with baking parchment.
Soak the Medjool dates in warm water for 10 minutes if they are firm. Drain well.
Blend the dates with the almond butter, vanilla and milk until smooth.
In a large mixing bowl combine the whey protein, oat flour, ground almonds, flaxseed, chia seeds, cacao powder, cinnamon and sea salt.
Pour the wet mixture into the dry ingredients.
Mix thoroughly until a firm dough forms.
If the mixture feels too dry, add a tablespoon of milk at a time.
Fold in any optional ingredients.
Press firmly into the prepared tin using the back of a spoon.
Refrigerate for at least 2 hours until firm.
Slice into 12 equal bars.
Store refrigerated.