For the frangipane: Pulse
together the butter, sugar, ground almonds, yolks, and vanilla extract in a food processor
. Refrigerate the mixture until chilled.
For the tart: Preheat an oven to 400 degrees F.
Slide a baking tray in the oven to heat. Lay the puff pastry
sheet onto a separate baking tray, lined with parchment. Trim off the edges of the pastry, this will make the edges rise more easily when baking. Using the point of a sharp knife, score
a 1/2-inch border around the edge of the puff pastry, being careful not to cut right through the sheet. Prick the entire surface, with a fork and brush with the egg yolk. Within the scored border, spread the prepared frangipane
evenly over the pastry. Place the cherries, cut side up, in a single layer over the frangipane. Carefully, place the tart on the hot tray, and bake for 15 minutes.
Remove the tart from the oven, and sprinkle with an even layer of sugar, and bake until its sides are golden and puffed, about another 5 to 10 minutes. Serve the tart
with some whipped cream, if desired.