In a food processor, combine flour, salt, sugar and cinnamon and pulse once to mix.
Add the cubed butter and process until it’s incorporated and the mixture looks like sand.
Add in cold water and pulse until the mixture holds together.
Transfer the mixture on a plastic wrap and form a ball. Don’t work on it too much. Wrap it well and chill in the refrigerator for 30 minutes.
On a lightly floured board, roll it into a circle about one inch wider than your pan. Carefully transfer it into a 9-inch tart pan with a removable bottom. Push the crust into the indentations in the sides. If you find it difficult, you can put the dough right into the pan without rolling out and press to fit the pan. Press the dough up higher than the tart pan and trim the edges using a rolling pin. Poke the bottom of the crust with a fork.
Chill at least half an hour.
Preheat oven to 375F. Line the chilled tart crust with parchment paper. Fill with dry beans and bake for 30 minutes.
To make the filling, add the flour and sugar to a bowl, and whisk until they are mixed. Whisk in the eggs one by one, beating until they just begin to lighten. Then whisk in the kefir.
Pour the kefir mixture into the crust, and bake for about 40 minutes, until the filling settles.
Sprinkle brown sugar on both sides of 6 persimmon slices. Cook them over medium height until slightly brown on both sides, about 5 minutes.
Remove the crust from oven, top with cooked persimmon slices, put it back into the oven and bake for another 5 minutes.
Let it cool completely and top with fresh pumpkin slices right before serving.