In a medium sized bowl mix together the berries with 2 tablespoons of sugar, 2 tablespoons of limoncello, and 1 teaspoon of lemon zest. Cover with plastic wrap and set in the refrigerator until you are ready to serve the panna cotta.
In a small microwave safe dish, combine the cool water with the gelatin powder. Let sit until the gelatin has absorbed all of the water. Set aside.
In a medium sized bowl mix together the cream, half and half, the remaining sugar, and the remaining limoncello. Heat the cream mixture over medium high heat, stirring slowly, until it comes to a boil.
While the cream mixture is heating up, place the dish of gelatin into the microwave. Heat for 5 to 10 seconds until the gelatin has become a liquid again.
Once the cream mixture comes to a boil (be careful not to let It boil over). Turn the heat down and let the cream simmer for 2 to 3 minutes, then add the liquefied gelatin. Let simmer for another 2 to 3 minutes while stirring slowly. Remove from heat.
Prepare your ramekins by spraying very lightly with oil.
Pour the panna cotta mixture into the ramekins evenly.
Cover the ramekins with plastic wrap and place in the refrigerator immediately. Let the panna cotta chill in the refrigerator until solid, at least 4 hours, or overnight.
When ready to serve. Invert the ramekins with the panna cotta onto a plate. You may find that using a thin knife to loosen the edges of the panna cotta from the ramekins before inverting may help.
Remove the berries from the refrigerator and give a nice gentle stir.
Top the panna cotta with a large spoonful of the berries. Garnish with a lemon peel, twist and a leaf of mint.