1.Grease and line the bottom and sides of a 20cm square tin with baking paper and set aside.
2.Wash and dry the rhubarb,trimming away any green (poisonous!) leaves. If stalks are thicker than 2cm,halve by cutting lengthwise. If making the grid pattern,cut the stalks into batons,each about 6.5cm long.
3.Place the sugar in a bowl and rub in the anise and vanilla seeds with your fingers. Toss the rhubarb pieces through the sugar and macerate for five minutes.
4. Start by laying the rhubarb batons horizontally in one corner of the lined tin,making sure there are no visible gaps between the stalks. Moving across the tin,lay the next batch of batons vertically,followed again by horizontally. Keep repeating until the rhubarb fills the tin. By laying the stalks in this manner,you'll create a series of squares. Sprinkle any of the remaining vanilla anise sugar over the rhubarb and set the tin aside.
5.Preheat the oven to 180C (160C fan-forced).
6. For the cake,sift the flour and salt together in a small bowl. Add the almond meal to combine,then set aside for the time being. Place the butter and sugar in the bowl of an electric mixer fitted with the paddle attachment and beat on medium speed until light and fluffy,about two minutes. Stop the mixer a couple of times to scrape down the bowl with a rubber spatula to ensure it is evenly mixed.
7. Add the eggs,one at a time,and beat until combined,then spoon in half the flour mixture. Beat on low speed until just incorporated,about 10 seconds,then remove the bowl from the machine and fold in the remaining dry ingredients and almond (or vanilla) extract with a rubber spatula.
8. Spoon the batter carefully over the rhubarb and spread with a spatula to form an even layer. Place on the middle rack of the preheated oven and bake for 60 to 70 minutes,until a skewer inserted into the middle of the cake comes out clean. Remove the cake from the oven and allow to cool for an hour before turning the tin upside down onto a serving plate. Serve with whipped cream. The cake is best served on the day it is made,but may be kept in a cool place for up to two days.
If you like this recipe,try Helen'scumquat and almond upside-down cake.
Find more of Helen Goh's recipes in theGood Food Favourite Recipes cookbook.