Place crust in an ungreased 9-inch pie plate; trim off excess pastry along edges. Fold edges under and crimp. Fill with pie weights, rice, or dried beans. Bake at 375° for 10 to 12 minutes or until just beginning to brown. Cool; remove weights.
Heat olive oil and butter in a large skillet over medium heat. Add onions; cook, covered, 30 to 40 minutes or until golden. Remove from heat. Add salmon and cheese; blend well.
Combine eggs and next 3 ingredients in a small bowl with a wire whisk. Stir in salmon mixture. Pour mixture into prepared crust.
Bake at 350° for 40 to 45 minutes or until center is set. Let stand 10 minutes. Garnish with fresh basil, if desired.
Wine note: The sweetness of the onions and the power of salmon are the key components. Again I gravitate to Germany with something a bit more substantial. Try Josef Leitz Rudesheimer Magdalenenkreuz Riesling Kabinett 2002 ($18)--Steven Geddes