For the tart crust:

1. Combine butter and sugar in the bowl of a stand mixer fitted with a paddle attachment and cream until light and fluffy. 
2. Add egg yolk and mix until incorporated.
3. Turn mixer to low and add flour and salt. When dough is almost together, add cream.
4. Shape dough into a disc, wrap, and chill for 20 minutes.
5. Roll dough on floured surface to ¼ inch thick, transfer to tart pan.
6. Line shell with parchment paper and pie weights and bake at 325 degrees until done.

For the curd:

1. Over double boiler, combine sugar and fruit purée, then add egg yolks and soft butter.
2. Using spatula, mix over heat until mixture is thick enough to coat the back of a spoon.
3. Pour through strainer into baked tart shell until shell is half full.
4. Refrigerate until cool. You may have curd left over.

For the truffle:

1. Steep mint sprigs in hot cream for 15 minutes, then strain and discard mint.
2. Chop chocolate to very fine, scald cream, and pour over chocolate, stirring to melt and combine.
3. Add corn syrup.
4. Pour this mixture into tart shell to fill.
5. Refrigerate until set, one hour.

For the fluff:

1. Combine all ingredients in metal bowl, whisk over double boiler until mixture is hot, about 160 degrees, and sugar is fully dissolved.
2. Pour mixture into clean mixer bowl and whip on high using whisk attachment until mixture has cooled to room temperature and is very white and fluffy.
3. Pipe mixture onto tart in desired pattern, use torch to toast fluff.