In a medium saucepan, combine blueberries,water, maple syrup and herbs.
Bring to a simmer over high heat, stirring constantly until the liquid has thickened and berries have popped, about 3-5 minutes.
Remove from heat and transfer into a heat-proof bowl or measuring cup and purée using an immersion blender. You can also transfer into a standing blender and purée until smooth.
Refrigerate until completely chilled.
Make Berry Cream.
Whip cream, sugar and salt in a standing mixer or large bowl until stiff peaks form and it starts to look a little lumpy (this is generally considered "over-whipped").
Pour in 1/2 cup of chilled bb syrup (reserve remainder for the assembly), and whip on high to incorporate.
Using a rubber spatula, scrape down the bowl, then whisk one more time to assure that streaks don't remain.
Distribute the remaining berries between 4 serving bowls or glasses.
Dollop the berry cream over top of each, and drizzle with remaining berry syrup. Finish with an herb garnish. Serve cold.
Note: the syrup can be refrigerated in an airtight container for a week, and the berry cream can be made and refrigerated for up to 24 hours. You can assemble the fools ahead of time in the serving vessels minus the syrup and garnish, covered in plastic wrap and refrigerated for up to 24 hours.