1Heat oven to 350°F. Spray 9-inch square pan with cooking spray.
2In small bowl, stir together caramel topping and sea salt; set aside. In medium bowl, mix flour, baking soda, table salt, cinnamon and nutmeg. In large bowl, beat butter and brown sugar with electric mixer on medium speed until light and fluffy, about 2 minutes. Add egg, vanilla and pumpkin; beat until well blended. Slowly add flour mixture, beating just until combined. Spread half of the batter in pan.
3Bake 10 minutes; remove from oven. Pour 3/4 cup of the reserved caramel topping over partially baked crust. Spread remaining batter over caramel.
4Bake 30 to 40 minutes longer or until toothpick inserted in center comes out clean. Cool completely in pan on cooling rack, about 1 hour. Cut into 4 rows by 4 rows. Sprinkle with powdered sugar. Drizzle with remaining caramel topping.