To make the ganache, place the cream in a pan and bring to 80C. Add the tarragon and let it infuse for 10 minutes.
In a separate bowl place the chocolate and melt on bain-marie. Gently add the strained cream and mix well. Add the soft butter and let it cool completely.
Place the 8 discs of puff pastry in a baking tray, brush them with the egg yolk and sprinkle with the sugar. Bake at 180C for 10 minutes.
Wash and cut the strawberries. Place a spoon full of chocolate ganache in the center of 4 pastry discs, place the strawberries around the ganache and place the rest of the discs on the top. Add the cherries and the cream.