Blubarb tray cake

140g all purpose flour

45g buckwheat flour 

1 tsp baking powder

1/2 tsp baking soda

250g greek yogurt or sour cream 

145g unsalted butter, softened 

230g sugar, divided 

2 tsp vanilla 

2 eggs

1 cup blueberries

1 1/2 cup sliced rhubarb 

For the crumble

80g flour

80g ground almond or walnut

80g brown sugar

80g chilled unsalted butter

1 tsp cinnamon

1 tsp cardamom

1/4 tsp salt

1. Preheat oven to 350

2. To make the crumble, finely dice the butter. Combine the remaining ingredients in a bowl. Using your fingertips work the butter into the mixture until evenly mealy. Place in fridge while you make the rest of the cake

3. Mix the rhubarb and blueberries with 30g of sugar, set aside

4. In the bowl of a stand mixer fitted with the paddle attachment, beat butter with remaining sugar and vanilla until fluffy.

5. Add in eggs and continue to beat until light and fluffy

6. Add in flour, baking soda and powder and mix on slow. Add in sour cream and stir until just combined

7. Transfer to a greased baking dish. Top with fruit, then sprinkle crumble over, bee for 20 wish minutes