Preheat oven to 350 F. Grease the cake tins and apply a parchment round to the bottoms
Combine cake mix and pudding mix in the bowl of a stand mixer fitted with paddle attachment. Add water, oil and eggs and mix on medium-low for a few minutes until well combined
Use a kitchen scale to measure equal amounts of batter into each of the 3 tins. Smooth tops
Leave to rest on the counter for 15-30 minutes to settle
Bake at 350 F for 30-35 minutes or until center is just moist and cake springs back when pressed (ours took closer to 35 minutes)
Cool in pans on wire rack for at least 15 minutes and then remove to cool fully on racks. Once cool place in fridge until ready to frost
Prior to frosting make your vegan buttercream
To begin to assemble cake, put your bottom layer on parchment then on a flat surface. Fill a round tip piping bag with vanilla buttercream and pipe circles onto the top of the first layer. Place the second layer on top and them apply a crumb coat to the sides
Using the same piping bag pipe a round border onto the top of the 2nd layer, then fill the center with passionfruit curd (or with frosting, if you don't have curd). Put on the third tier and crumb coat the remainder of the cake
Chill the cake briefly. Color a portion of your frosting with pink coloring or whatever you choose. Fit a piping bag with an open star tip and remove your cake. Pipe rosettes and starts onto the top and chill cake prior to serving