Over low heat, mash and cook berries until they are runny and jam-like.
Remove from heat and place in fridge until cool.
Spread jam on bread and place an additional piece of bread on top to create a sandwich.
Cut lengthwise or use cookie cutters to cut.
If your berries are very dry or don't give you enough juice to cook the berries without burning them, you can add water, 1 tablespoon at a time, as needed. But don't go overboard or your jam won't thicken.
Please note that the nutrition data given here is a ballpark figure. Exact data is not possible.