1. Preheat oven to 375 degrees. Make the frangipane: In the bowl of a food processor, combine butter and sugar. Process until smooth. Add eggs, salt, and almond extract. Pulse to combine. Add almond and all-purpose flours, and process until a fine paste forms. Set aside.

2. On a lightly floured surface, roll pate sucree dough into a 12-inch circle. Fit circle into a 10-inch tart tin with a removable bottom, being careful not to stretch dough too thin. Spread 3 tablespoons jam into bottom of lined tart tin.

3. Transfer frangipane to a pastry bag fitted with a 1/2-inch tip. Pipe evenly over jam. Arrange plum wedges over frangipane in a circular pattern, closely overlapping wedges and completely covering frangipane. Sprinkle with sugar. Bake until crust is golden and plums are cooked through and beginning to caramelize, 1 hour to 1 hour and 15 minutes. Transfer to a wire rack, and let cool.

4. In a small saucepan, melt remaining 3 tablespoons jam. Brush evenly over cooled tart. Serve at room temperature.