Add chilled butter, and ⅔ cup sugar to the bowl of a food processor, and process until combine.
Add salt, vanilla extract, 2 egg yolks and process again.
Add flour, one cup at a time, and process to form a dough.
Remove the dough to a plastic wrap and press to form a smooth disc using the wrap without touching the dough.. Chill the dough for, at least, 30 minutes.
Roll the dough out to ⅛-inch thickness, and line a 9-inch removable bottom tart pan with pastry and press in the bottom and into the fluted edges.
Overhang can be removed by running a rolling pin over the edge of the tart pan to get a smooth edge.
Prolonged working with the dough makes it soft and it should be returned to the refrigerator to firm up before baking for better end result.
Remove from oven and place on a rack to bring it to room temperature.
Sour cherry jam:
Stir the sour cherry jam in a small bowl until it is very smooth. Set aside.
Spread well stirred sour cherry jam in the bottom the pastry lined tart pan evenly and smoothly.
Frangipani:
Meanwhile, prepare frangipani paste by grinding almonds and sugar in a processor until it becomes a powder.
Add teaspoon salt, ½ teaspoon almond extract, 6 tablespoons room temperature butter, 1 large egg, 2 tablespoons flour, and 1 tablespoon rum, if using.
Spread frangipani paste over the layer of jam in the tart pan and smooth it out using an offset spatula.
Place the tart pan in a baking tray, and bake in a 350° F preheated oven for 30 to 35 minutes. If it starts to overbrown, cover with foil until it bakes for the requied amount of time. Once ready, remove from the oven and set aside until it comes to room temperature.
Glaze:
To make the glaze, sift 1 cup powdered sugar to remove lumps.
Add lemon juice in very small amounts while stirring to mix to prevent the glaze from thinning out too much. Once the glaze is at a right pouring consistency, squiggle over the tart and let it set before cutting into wedges to serve.