Bake cake in an oblong pan (27.5 x 22.5 x 5cm.), as directed on package.
Cool and cut cake crosswise in half. Reserve one half for another dessert.
Slice bananas.
Cut remaining cake into 8 pieces, splitting each piece horizontally.
Arrange half of the pieces in a 2 litre glass serving bowl, cutting pieces to fit, arrange half of the banana slices over the cake.
Spread with 1 cup of the pudding, all of which has been blended with the additional milk to make a loose custard.
Repeat with remaining pieces of cake banana slices and pudding.
Cover and chill for at least 4 hours.
In a chilled bowl, beat the cream and granulated sugar until stiff, and spread over the trifle.
To Serve: Sprinkle with toasted almonds and attractively arrange arrange the maraschino cherry halves.