Put a dessert shell in a toaster oven or regular oven. Just warm it up, don't get it crispy.
Put the berries in a small bowl and microwave for 1½ minutes. They should bubble vigorously.
Add the brown sugar Swerve, if using, to the berries and stir to combine - be careful, the bowl will be hot. Pour mixture into the warmed dessert shell, and top with whipped cream. Yum!
Notes
In the US, 60 calorie spongecake dessert shells are found in the supermarket - usually in the bakery section near the cakes. I'm not sure of their availability in other countries.You can use other berries, or even other fruit, just be sure to check the calorie count because it may be different.