Preheat the oven to 375 degrees. Grease a muffin tin with nonstick spray. Place a puff pastry square inside the well of a muffin tin.
In a large saucepan, bring cherries, sugar, lemon zest, and water to a boil. Reduce heat; simmer and stir until thickened. Cool slightly.
Spoon the cherry mixture inside the puff pastry square and bake in the oven for 15 to 20 minutes until the puff pastry is cooked. Let cool for 5 minutes.
Spoon creme fraiche over top and garnish with mint.