Mix flour, sugar and salt in food processor with a few on/off turns.

Drop butter pieces into food processor bowl and pulse 6-8 times, until coarse meal forms.

Mix egg yolk and juice together, then add to bowl. Pulse a few times until dough gathers together. If more liquid is needed, add juice by one tablespoon at at time.

Transfer dough to floured plastic sheet and shape into disc. Flour the top lightly, wrap tightly in plastic and refrigerate for 30 minutes.

Roll dough between two pieces of wax paper to fit into tart pan--about 1/16 inch thick. Transfer dough to tart pan and refrigerate for another 30 minutes.

Preheat oven to 400 degrees.

Pierce dough with fork in several places. Smear butter on one side of a piece of aluminum foil big enough to cover tart crust bottom and sides. Place butter side down onto crust and fill with rice, dry beans, or pie weights. Bake until sides are set, about 10 minutes.

Remove crust from oven and take off foil and pie weights. Return crust to oven and bake an additional 10 minutes, until golden brown. Check on the crust a couple of times and pierce any bubbles that form in the crust with a fork.

Cool completely at room temperature before filling.