Directions

1. In a small mixing bowl, combine flour, 1/2 cup sugar, baking powder, cinnamon and salt. Whisk the egg yolks, water, oil and vanilla; add to dry ingredients. In another small mixing bowl, beat egg whites and cream of tartar on medium speed until soft peaks form. Gradually add remaining sugar, 1 tablespoon at a time, beating on high until stiff peaks form. Fold into batter.
2. Gently spoon into an ungreased 7-in. tube pan. Cut through batter with a knife to remove air pockets. Bake on the lowest oven rack at 350 degrees F for 40-50 minutes or until top springs back when lightly touched. Immediately invert pan; cool completely, about 1 hour.
3. Run a knife around side and center tube of pan. Remove cake. Cut a 3/4-in. slice from top of cake; set aside. Using a sharp knife, carve a tunnel out of cake, leaving a 1-in.-thick wall on all sides; carefully remove cake from tunnel. (Discard cake from tunnel or save for another use.)
4. For filling, in a small mixing bowl, beat cream, confectioners' sugar and vanilla until soft peaks form. Set aside two-thirds of mixture. Fold remaining cream mixture into the strawberries; spoon into tunnel. Replace cake top. Frost top and sides of cake with reserved cream mixture.