For the cake – butter a 9 x 13 pan, line it with parchment, butter the parchment and preheat the oven to 350.  Stir together the 3 rhubarb mix ingredients in a medium bowl and set aside.

Using your electric mixer, cream together the butter, sugar and lemon zest for a couple of minutes until fluffy, then beat in the eggs, one at a time, scraping down the bowl between additions.  In a small bowl, whisk together the flour, baking powder, salt and ginger and add about 1/3 to the batter, mixing until just combined.  Add half the sour cream, mix, then the second third of the flour mix, stir again, then the remaining sour cream and the remaining dry mix.  Scrape down the bowl and mix for another few seconds until completely combined.

Evenly dollop the batter over the bottom of your prepared pan and use an offset spatula to spread it out into an even, thin layer.  Scrape the rhubarb mix evenly overall, aiming to have the rhubarb pieces in a single layer.  Stir together the crumble mix, adding the melted butter last, and then scatter as evenly as possible over the rhubarb.

Bake for about 55 minutes until the lowest layer of batter is cooked through and the crumble topping is a lovely golden brown.  It’s very difficult to tell when this cake is done because of the juicy rhubarb mix so if you’re unsure, an extra 5 minutes shouldn’t hurt.  This is also a very moist cake and it’s unlikely to dry out with all of the fruit

Allow the cake to cool completely before removing it from the pan with the parchment handles to a cutting board.  Slice as you wish and be sure to share – you’ll be baking this again soon!