The travelers had been picking wild fruit since late May, but this is the first mention of making pastry. Clark compared the buffalo berry to plums he knew from the East: the pivet (Ligustrum Vulgare) and the damson (Prunus Domestica Institia).

1 cup all-purpose flour
1/4 cup whole wheat flour
1/2 teaspoon salt
1/4 cup lard or vegetable shortening
4 tablespoons butter
2 to 3 tablespoons cold water

Filling:
1 1/2 to 2 pounds ripe fresh plums, pitted and sliced (see note below)
1/3 cup all-purpose flour
1/3 to 1/2 cup sugar

Preheat oven to 375°F.

To make the pastry, combine the flours and salt in a medium mixing bowl. Cut in the lard and 3 tablespoons of butter with 2 knives or with a pastry blender until the mixture is the size of shelled peas. Add the water, 1 tablespoon at a time, and stir until the pastry holds together. Chill about 20 minutes. Roll out the pastry to a 10-inch circle on a lightly floured surface. Carefully transfer the pastry circle to an ungreased baking sheet.

To make the filling, toss the plums gently with the flour and sugar in a large bowl. Arrange the plums over the pastry, leaving 1 inch of pastry around the edge. Fold the pastry edge over the plums. Dot the plums with 1 tablespoon of butter.

Bake for 40 to 45 minutes, or until the plums are tender. Cool for at least 15 minutes before serving.

Note: Very ripe plums will be sweeter and juicier and will make the texture of the tart softer.