Rhubarb, vanilla and sour cream crumb cake

I buy Delicious Magazine every month and really enjoy flicking through the pages, even if I don't make many of the recipes!  The cover recipe really caught my eye, it was a tasty looking rhubarb cake and inside there was a whole selection of rhubarb recipes.  I love rhubarb, and had real trouble choosing which one to make, pie, cake or cheesecake?  In the end I went with the cake, but I think the cheesecake will be next (and soon!)

I was supposed to be going to have lunch with the girls from my ante-natal class today, and had decided to make the cake to celebrate the fact that all eight of us finally joined the mum club.  Sadly, because of Chicken's snuffles, we couldn't go (didn't want to infect the other babies), but since I'd already made the cake I thought I'd share it with you.  I made a few changes to the original recipe, using rice flour and gluten free baking powder because of of the girls can't eat wheat.   Final verdict, it tasted great!

Gluten Free Rhubarb, Vanilla and Sour Cream Crumb Cake

225g trimmed rhubarb
50g caster sugar
2tsp rice flour

For the cake:
6tbsp sour cream
1 large egg plus one egg yolk
1tsp vanilla bean paste
100g rice flour
100g caster sugar
1/2 tsp baking soda
1/2 tsp gluten free baking powder
1/4 tsp salt
75g unsalted butter, at room temp
50g ground almonds

For the crumbs:
50g unsalted butter
25g light brown sugar
40g caster sugar
1/2 tsp vanilla bean paste
100g rice flour
pinch of salt

1.  For the crumbs, melt the butter (stove or microwave) add both types of sugar and stir constantly until dissolved into a smooth, toffee like paste.  Stir in the vanilla paste, then the flour and salt to make a biscuit-like dough.  Press the mixture firmly into the bottom of the bowl and set aside to cool.
2.  Pre-heat the oven to 180c and grease and line a 23cm round cake tin with baking paper. 
3.  Cut the rhubarb into 1in pieces and put in a mixing bowl.  Add the sugar and flour and mix till the rhubarb is thoroughly coated.  Set aside for 15mins or so, stirring occasionally so that the dry ingredients sticks to the fruit.  Set aside.
4.  For the cake, mix the sour cream, egg, yolk, and vanilla in a small bowl.  Sift the flour, sugar, baking soda, baking powder and salt into another bowl.  Add the butter and mix using a electric mixer until the mixture looks like breadcrumbs.  Stir in the mixed almonds and gradually beat in the wet ingredients until smooth.
5.  Spread the cake mixture into the base of the tin and scatter over the rhubarb mixture.  Break the crumbs into small pieces and scatter over the cake.
6.  Bake for 40-45 mins until golden and a skewer comes away clean when inserted into the cake.  NB if the skewer hits a piece of rhubarb it will still be moist.
7.  Dust with icing sugar and serve either warm or cool.