Combine apples with lemon juice in medium-size bowl; toss to coat apples. Stir in the 1/4 cup sugar, the flour and cinnamon.
Roll pie pastry out on lightly floured surface into 14-inch circle. Carefully roll pastry back onto rolling pin; unroll pastry onto large ungreased baking sheet.
Heat oven to 400°F.
Mound apple filling onto center of dough, leaving 2-1/2-inch border all around edge. Cut up butter into small pieces. Dot apple filling with butter. Fold uncovered pastry border up and part-way over apple filling, working all around galette. Brush top of pastry edge with milk. Sprinkle with the 1 tablespoon sugar and the nuts.
Bake in 400°F oven or until filling is hot and crust is golden, about 40 minutes. Brush top evenly with apricot preserves. Cut galette into wedges, and serve warm or at room temperature.
Mix all-purpose flour and salt. With pastry blender or finger-tips, rub unsalted butter, cut into pieces and chilled and vegetable shortening, cut into pieces and chilled into flour mixture until texture of coarse meal. Gradually add cold water, tossing with fork, until mixture begins to mass together. Shape into ball. Flatten into disk. Cover with plastic wrap. Refrigerate until well chilled, about 30 minutes.