1 1⁄4 cups flour
1⁄2 tsp. salt
2 oz. chilled butter, cut into pieces
2 tbsp. olive oil
2 tbsp. water
3 tbsp. olive oil
2 1⁄2 lb. onions, thinly sliced
3 garlic cloves, minced
1⁄2 tsp. thyme
Salt and pepper, to taste
1⁄2 pt. cherry tomatoes, halved
2 dozen farmed mussels, steamed and shelled
1⁄2 cup niçoise olives
Slivered fresh basil leaves
1. For crust: Mix flour and salt in food processor. Add butter and oil and process until mixture forms coarse meal. Add water, a little at a time, until dough starts to hold together.
2. Form dough into a disk; wrap and chill at least 2 hr.
3. For filling: Heat 21⁄2 tbsp. oil in a large, heavy sauté pan over med.-low heat. Add onions, garlic, and thyme. Cook until onions are tender and caramelized, about 45 min. Increase heat, if necessary, to evaporate liquid. Season with salt and pepper; cool.
4. Preheat oven to 425°F. Lightly grease large baking sheet. Roll out dough to 12-in. square and place on sheet. Pinch dough to form a rim around the edges. Spread onion filling evenly on top.
5. Bake pissaladière 30 min., or until golden and crisp.
6. Heat remaining 1⁄2 tbsp. oil in a sauté pan. Add tomatoes and mussels; sauté 1 min. Stir in olives to heat through.
7. Arrange tomatoes, mussels, and olives on top of pissaladière. Garnish with basil.