1. Preheat oven to 350°. Beat 1/4 cup granulated sugar, butter, and 1 tsp. zest at medium speed with a heavy-duty electric stand mixer 2 minutes or until creamy. Stir together 2 cups flour and 1/4 tsp. salt. Gradually add to butter mixture, beating until just blended. Coat a 13- x 9-inch pan with cooking spray. Press dough into bottom of prepared pan. Chill 15 minutes.
2. Bake at 350° for 15 to 20 minutes or until lightly browned. Remove from oven; reduce oven temperature to 325°.
3. Whisk together eggs and 2 cups sugar. Process ginger and 1/2 cup flour in a food processor 1 minute or until ginger is finely chopped. Stir in baking powder. Whisk ginger mixture into egg mixture. Whisk in lemon juice and remaining 2 Tbsp. lemon zest; pour over crust.
4. Bake at 325° for 15 to 20 minutes or until filling is just set. Remove from oven.
5. Stir together remaining 3/4 cup flour, 1/2 cup sugar, and 1/4 tsp. salt in a small bowl. Stir in melted butter until well blended. Stir in almonds. Sprinkle over hot lemon mixture, and bake 20 to 25 more minutes or just until lightly golden. Cool completely in pan on a wire rack (about 1 hour). Cut into squares.