Rhubarb upside-down cake

1 hour 5 minutes (+ standing) 400g rhubarb (see Tips)

½ cup (110g) caster sugar

40g butter, melted, cooled

185g butter, extra, at room temperature 1 teaspoon vanilla extract

1 cup (220g) caster sugar, extra

3 eggs

1⅔ cups (225g) gluten-free self-raising flour ⅓ cup (40g) gluten-free custard powder ½ cup (125ml) buttermilk

SERVES 8

1 Preheat oven to 180°C. Grease a deep 23cm square cake pan; line the base and sides with baking paper.

2 Cut rhubarb into 23cm long pieces (see Tips). Combine rhubarb, sugar and melted butter in a large bowl; stand for 5 minutes. Arrange the rhubarb in a single layer over the base of the lined pan; top it with the remaining sugar mixture.

3 Beat the softened butter, vanilla and extra sugar in a medium bowl with an electric mixer until pale and fluffy. Beat in the eggs, one at a time, until well combined. Stir in the sifted flour and custard powder, alternating with the buttermilk.

4 Drop spoonfuls of cake mixture gently over the rhubarb in the pan, then smooth the surface.

5 Bake cake for 55 minutes or until a skewer inserted into the centre comes out clean. Leave cake in pan for 15 minutes before carefully inverting onto a serving plate or cutting board.

You may need to purchase two bunches of rhubarb to ensure that all the stalks are of an even thickness to achieve the striking patterned top. Select bunches of rhubarb with the reddest stems. If the rhubarb stalks are thick, cut in half lengthways before tossing in the sugar and butter; place cut-side up in the base of the pan.