1. Preheat oven to 425°F. Coat 9-inch pie plate with cooking spray.
2. Toss Brussels sprouts with 1 Tbs. oil in large bowl. Season with salt and pepper, if desired. Spread on baking sheet, and roast 10 minutes, stirring once, or until browned. Set Brussels sprouts aside, and reduce oven temperature to 400°F.
3. Meanwhile, purée beans and remaining 2 Tbs. oil in food processor until smooth.
4. Roll puff pastry sheet into 12-inch square. Press into prepared pie plate. Let overhang 1/2-inch around edges, and trim any remaining pastry with paring knife. Prick bottom all over with fork. Bake 15 minutes, or until golden.
5. Spread bean purée in hot crust; top with roasted Brussels sprouts, and sprinkle with pomegranate seeds.