In a small saucepan on low heat, gently melt and stir coconut oil until it has a smooth and creamy consistency. You can also do this in the microwave by heating in 30 second intervals on 2% power.
Working in 2 parts, stir in the peanut butter and optional flax seed. Whip together until smooth.
Spoon 1 teaspoon of peanut butter mixture into mini muffin liners. Place in the freezer for 10 minutes.
Add 1 teaspoon of jam to each cup. Dollop jelly in the center of the peanut butter base and squish the jelly into a uniform thickness, leaving space around the edges so that the jelly does not touch the liner.
Top with ½ -1 tablespoon of peanut butter mixture and place in the freezer for 30 minutes.
If garnishing with salt, freeze for 1 minute, top with salt and return to freezer.
Store in the fridge or freezer and serve chilled.