Unroll piecrust-dough sheets on a lightly floured surface. Using a 4-inch round cutter, cut 6 circles from dough. Press each circle into a 3¾-inch tart pan, trimming excess dough. Refrigerate until ready to fill.
In the work bowl of a food processor, combine almonds and sugar, pulsing just until sandy. (Do not overprocess.) Add butter, pulsing until blended. Add eggs, pulsing until blended. Add flour and vanilla, processing until all ingredients are incorporated. Divide mixture evenly among prepared tart pans. Place tart pans on a rimmed baking sheet.
Bake until light golden brown and firm, 12 to 15 minutes. (Filling will puff while baking and fall while cooling.) Cool completely on wire racks before removing tarts from pans.
In a small microwavable bowl in a microwave oven or in a small saucepot, heat apricot jam just until warm, stirring occasionally. Brush each tart with approximately 1 tablespoon jam. Arrange 5 sections blood orange in a fan pattern on top of each tart. Brush with remaining apricot jam.
Garnish with a mint leaf, if desired. Keep chilled until ready to serve.
Recipe by TeaTime Magazine at https://teatimemagazine.com/blood-orange-tarts-recipe/