1 can (15 oz.) pumpkin puree
3/4 c. firmly packed light brown sugar
8 oz. creme fraiche
3 large eggs
1 tsp. cinnamon
1 tsp. ginger
1/4 tsp. nutmeg
1/4 tsp. salt
1/8 tsp. cloves
2 oz. quality semisweet chocolate
1 c. flour +
1/4 c. plus 1 T sugar
1/4 c. unsweetened cocoa powder
1/2 tsp. salt
1/2 tsp. cinnamon
1/4 tsp. cloves
1 stick cold unsalted butter, cut into small pieces
4 oz good quality semisweet chocolate, finely chopped
Preheat oven to 350º
In the bowl of an electric mixer fitted with the paddle attachment, combine flour, sugar, cocoa, salt, cinnamon, and cloves. Add butter; mix on low speed until butter is the size of small peas, about 5 minutes. Add egg; mix until ingredients come together to form a dough.
On a lightly floured work surface, roll out dough to just thicker than 1/8". Brush off excess flour; transfer dough to a 10" tart pan with a removable bottom. Press dough into bottom and up sides of pan; trim excess flush with edge. Lightly prick bottom of dough all over with a fork. Chill until firm, about 30 minutes.
Bake shell until firm, about 15 minutes. Immediately sprinkle chocolate over bottom of shell; smooth with a spatula.
In a medium bowl, whisk together pumpkin puree, brown sugar, creme fraiche, eggs, cinnamon, ginger, nutmeg, salt and cloves until smooth. Pass mixture through a fine sieve set over a clean bowl; discard solids. Pour filling into prepared crust.
Bake until filling is set, about 40 minutes. Transfer to a wire rack, and let cool at least 30 minutes.
Set a heatproof bowl, or the top of a double boiler, over a pan of barely simmering water. Melt chocolate in bowl, stirring occasionally, remove from heat. Dip a spoon in the melted chocolate, then drizzle chocolate over tart, forming decorative stripes. Refrigerate until well set, at least 1 hour and up to 1 day.