1.Beat butter, sugar and egg yolk in a small bowl with an electric mixer until combined. Stir in sifted flour and ground almonds, in two batches. Turn dough onto floured surface; knead until smooth. Roll pastry between sheets of baking paper into a 3mm (⅛-inch) thickness; place on tray. Refrigerate 30 minutes.
2.Preheat oven to 220°C/425°F. Grease 12-hole (1½-tablespoon/30ml) shallow round-based patty pan.
3.Meanwhile, make almond filling. Beat butter, rind and sugar in a small bowl with an electric mixer until light and fluffy. Beat in eggs, one at a time. Stir in ground almonds and flour.
4.Cut 12 x 6.5cm (2½-inch) rounds from pastry; press rounds into pan holes. Divide jam between pastry cases, spoon filling into cases; place a cherry into the centre of the filling.
5.Bake tartlets about 20 minutes. Stand tartlets in pan 10 minutes before turning, top-side up, onto wire rack to cool.
If cherries are out of season you could use 425g (13½ ounces) canned seedless black cherries; drain cherries well and pat dry on absorbent paper towel before using. Tarts can be made a day ahead; store in an airtight container.Note