01 -
Get your oven hot at 350°F (175°C) and butter a 9-inch square pan thoroughly.
02 -
Grab a medium bowl and mix your flour, rising agent, and salt together well.
03 -
Take a big bowl and beat sugar with soft butter until it's fluffy. Add your egg and vanilla and mix it up good.
04 -
Start with flour, add some milk, more flour, more milk, ending with flour. Gently stir in your chopped rhubarb last.
05 -
Put all your mix in the buttered pan, make it even, and stick it in the oven for about 45-50 minutes. It's done when you poke it with a toothpick and nothing sticks.
06 -
Put butter, sugar, and thick cream in a pot on medium heat. Keep stirring until everything melts together smoothly. Turn off the heat and mix in vanilla.
07 -
Pour the warm butter sauce over slices of your fresh cake.