01 -
Preheat oven to 175°C. Lightly grease a 23 x 33 cm rectangular baking pan and set aside.
02 -
In a large bowl, cream the softened butter and granulated sugar together until light and fluffy. Beat in the eggs one at a time, then blend in the vanilla extract.
03 -
Fold in the Greek yogurt or sour cream until fully incorporated.
04 -
In a separate bowl, whisk together the flour and baking soda.
05 -
Gradually stir the dry mixture into the wet ingredients until just combined. Gently fold in two-thirds of the diced rhubarb.
06 -
In a bowl, mix the dark brown sugar, flour, and ground cinnamon. Using a pastry blender or fingertips, cut in the cold butter until crumbly.
07 -
Spread half the batter evenly in the prepared baking pan. Sprinkle with half the crumb topping and the remaining diced rhubarb. Dollop the rest of the batter on top and then finish with the remaining crumb mixture.
08 -
Bake at 175°C for 30–32 minutes, or until a toothpick inserted in the centre comes out with a few moist crumbs.
09 -
Allow to cool slightly in the pan. Serve warm or at room temperature.