01 -
Preheat oven to 175°C. In a large mixing bowl, whisk together the plain flour, white sugar, baking powder, and salt until thoroughly combined.
02 -
Add diced rhubarb, whole milk, and melted butter to the dry mixture. Stir just until the batter is evenly combined, taking care not to overmix.
03 -
Pour the batter into a greased 23 x 33 cm baking dish, spreading it evenly with a spatula. Bake for approximately 45 minutes, or until a toothpick inserted in the center comes out clean. Remove from oven and let cool slightly.
04 -
While the cake cools, combine unsalted butter, granulated sugar, and whipping cream in a heavy saucepan. Bring to a gentle boil over medium heat, stirring frequently. After reaching a boil, continue to stir and cook for 1 minute. Remove from heat and let the sauce cool slightly.
05 -
Cut the cake into portions and serve warm, drizzled generously with the butter sauce. Reheat sauce if needed before serving.