Heat oil in large skillet over medium heat. Cook onions with salt, stirring often, 15 to 20 min. until golden brown; cool completely.
Meanwhile, preheat oven to 425°F (220°C). Dust work surface with flour. Roll puff pastry to fit 15 x 10-in. (38 x 25-cm) baking sheet. Line baking sheet with parchment paper. Place pastry onto parchment. Score 1/2-in. (1-cm) border on all sides of pastry with tip of sharp knife. Prick pastry all over (except border) with fork. Spread onions inside border. Arrange anchovy fillets in diagonal pattern on top of onions. Scatter artichokes, tomatoes and olives over top. Sprinkle with goat cheese and herbes de Provence.
Bake 20 min. until pastry is golden brown and crisp. Cool on wire rack 10 min. before slicing. Serve warm or at room temperature.
Make twice the amount of caramelized onions and save the extra to toss with pasta, serve in sandwiches or with grilled meats.