Add all ingredients to a bowl and work the mixture with a fork until it reaches dough-like consistency.
Press the dough into an 8 or 9 inch round baking pan with removable bottom, or a tart pan with removable bottom, into a thin layer with sides that go up about 1 inch up.
Bake in a pre-heated to 325F oven for about 20-25 minutes. Remove from oven and let completely cool.
Make the sugar-free Frangipane or Almond Cream Filling:
Add 3/4 cup almond meal, 1 whole egg, 1 egg yolk, 5 tablespoons softened butter, 1 teaspoon almond extract and 1/2 cup SPLENDA® No Calorie Sweetener or granulated sugar. Work together with a fork, whisk, or a mixer until smooth mixture forms.
Add the Almond Filling to the pre-baked, completely cooled tart. Even it out along the bottom of the tart.
Wash and pit about 6 or 7 sweet/ripe plums (depending on the size you might need more or less). Cut each half into half again.
Put the plum quarters on top of the almond filling, cut side up, pressing them in. Sprinkle with couple tablespoons of almond slices.
Bake in a preheated to 325F oven for about 40-50 minutes or until the filling in the middle of the tart sets. Remove from the oven and allow to cool completely. Slice and enjoy.
For aesthetic purposes only - heat 2 tablespoons of jam (plum, peach, apricot or any other stone fruit jam) and brush onto the plums on top of the tart - this step is optional and will add sugar to the tart since the jam is not usually sugar-free.