CRUST
1 1/4 cups unbleached all purpose flour
1/4 cup sugar
1/4 teaspoon salt
1/2 cup (1 stick) chilled unsalted butter, cut into 1/2-inch pieces
1 large egg yolk
1 tablespoon (or more) ice water

MOUSSE
6 ounces good-quality white chocolate (such as Lindt or Baker's), chopped
1 1/4 cups chilled whipping cream

1/2 teaspoon vanilla extract
2 large egg whites
1/8 teaspoon cream of tartar

1/3 cup seedless strawberry jam
1 tablespoon fresh lemon juice
1 16-ounce basket strawberries, hulled, thinly sliced lengthwise