Preheat oven to 350°.
Place almonds in a food processor; pulse until finely ground. Lightly spoon flour into dry measuring cups; level with a knife. Add flour and next 5 ingredients (flour through salt) to food processor; process until combined. Add butter, water, and egg; pulse 3 or 4 times or just until combined.
Lightly press mixture evenly into bottom of a 9-inch round springform pan coated with cooking spray. Sprinkle with powdered sugar. Bake at 350° 30 minutes or until lightly browned.
Remove outer ring of springform pan, and cut cookie into 12 wedges while warm.