Line a regular muffin pan with 12 silicone or parchment paper liners. (I used a wilton heart shaped pan that was six much larger servings)
In a medium saucepan over medium heat, combine the frozen raspberries and strawberries. Bring to a boil and the reduce the heat and simmer 5 minutes. Mash the berries with a fork. Stir in stevia, you can keep adding until it's to the desired sweetness. Whisk in the grassfed gelatin and let cool while preparing the peanut butter mixture.
In a microwave safe bowl, combine the peanut butter and coconut oil. Cook on high for 30 to 60 seconds, until melted. Whisk in sweetener, depending on how sweet you like it you can add more. Add the vanilla and stir to combine.
Divide half of the peanut butter mixture among the 12 cups and set in the freezer to firm up, about 15 minutes. Divide the raspberry mixture among the cups and top with the remaining peanut butter mixture.
Refrigerate until firm. Keep refrigerated.