Step 1
To make the cake, in a bowl, stir 1¾ cups of boiling water, dates and bicarbonate of soda. Cover and soak for 4 hours or until dates are very soft.
Step 2
Position a rack in centre of oven and preheat oven to 175°C (155°C fan-forced). Generously spray a 20cm square baking pan with non-stick cooking spray and line base with baking paper.
Step 3
In another bowl, whisk flour, baking powder and salt. In a large bowl, using a handheld electric mixer, beat sugar and butter, scraping sides as needed, for about 3 mins or until fluffy. Add eggs, 1 at a time, beating well after each addition. Add vanilla and mix for about 1 min, or until mixture lightens in colour. Reduce speed to low and gradually mix in flour mixture and then date mixture, scraping bowl as needed.
Step 4
Pour the batter into the prepared dish. Bake, without moving, for about 1 hour 5 mins or until cake springs back when gently pressed and a toothpick inserted into centre of cake comes out with a few moist crumbs attached. Transfer to a rack and cool for 30 mins.
Step 5
Run a knife around edges to loosen cake. Invert cake onto rack and remove baking paper. Cool cake upside down on rack (this will help level it out).
Step 6
To make the vanilla toffee frosting, using a paring knife, scrape seeds from vanilla beans and place seeds in a large bowl with cream cheese, butter, sugar, and salt. Using an electric handheld mixer, beat on medium speed for about 6 mins or until smooth and fluffy.
Step 7
Halve cake horizontally into 2 even layers. Dab some frosting on a cake plate and centre 1 cake layer, cut-side up, on frosting. Brush away any loose crumbs from cake. Using an offset spatula or palette knife, spread 1½ cups of frosting over cake to form a smooth even layer. Top with other cake layer, cut-side down. Press firmly to adhere layers. Spread 2 cups of frosting over top and sides of cake to form a smooth thin layer. Refrigerate cake for about 30 mins or until frosting is not tacky.
Step 8
Spread the remaining frosting decoratively all over the cake to form a smooth coat. Refrigerate for 30 mins or until frosting is firm.