Preheat the oven to 425 degrees F. Line a baking sheet with parchment paper.
Use a biscuit or cookie cutter (I used one 2.5-3 inches in diameter) to cut rounds out of the pastry. I cut 6 rounds total. Place them on the parchment paper.
Place the raspberries in a bowl and toss with the sugar, flour and salt. Toss with the lemon juice.
Add some raspberries to the center of each pastry round. Top with the chopped chocolate - a tablespoon or 2. Save some chocolate to melt at the end.
Fold the edges of the pastry up over the raspberries, the whole way around.
Whisk together the egg and water, then use a pastry brush to brush the puff pastry. This will give it shine.
Place the sheet in the oven and bake for 12-15 minutes. These may need a little longer too! You want the pastry to be golden and puffed.
While they bake, melt the remaining chocolate. I just do this in the microwave. I melt for 30 seconds on 50% power and stir after each time until melted.
When the tarts are finished, drizzle more chocolate on top. Serve! These can be served warm or shortly after cooling.