the top is golden brown, about 35 to 40 minutes. let cool on a rack for 15 minutes. remove tart ring. serve warm or at room temperature.
beat together the butter and sugar in a medium-size bowl until creamy. add the salt, vanilla and egg yolk and mix until completely combined. add the flour and mix until there are no dry patches. wrap the ball of dough in plastic wrap and press into a 4" disk. chill several hours or overnight until firm.
place the dough between two pieces of parchment paper, lightly dusting the dough with some flour. roll out the dough into a 12 inch circle. the parchment paper will 