Free-Form Apple Or Pear Tart

Combine flour, salt and sugar in a food processor; pulse once or twice. Cut 8 tablespoons butter into chunks, and add it and egg yolk to flour mixture. Process until butter and flour are blended, about 10 seconds. Turn mixture into a bowl, and add cold water, a tablespoon at a time, stirring after each addition. After adding 3 or 4 tablespoons you should be able to gather mixture into a ball; wrap ball in plastic, and refrigerate for at least 1 hour (or freeze for about 15 minutes). Preheat oven to 400 degrees. Roll or pat dough into a 10-inch circle; it can be quite crude in shape. Place it on a cookie or pizza sheet, preferably nonstick. Arrange fruit slices on top, right out to edges; make the pattern attractive, if you like. Sprinkle with brown sugar. Cut remaining butter into bits, and top fruit with it. Bake until crust is nicely browned and fruit is tender, 20 to 30 minutes. Remove, and serve warm or at room temperature, with crème fraîche, whipped cream or ice cream.