1. Preheat your oven to 350 degrees F.

Rhubarb Mixture:

1. Add the chopped rhubarb and 3/4 cup sugar to a saucepan.
2. Cook over medium heat for about 15 minutes. The mixture is done when the rhubarb is tender. There should also be some syrupy juice in the pan.
3. Set aside to cool slightly.

Cake Batter:

1. Cream together the butter and 1/2 cup sugar.
2. Add the egg and mix until smooth. Set aside.
3. In a separate bowl whisk together the flour, baking powder and salt.
4. In a measuring cup mix together the milk and vanilla.
5. Add the flour mix to the butter mix, alternating with the vanilla milk.
6. Mix well.
7. Grease an 8 x 8 baking dish with butter, then pour the batter into pan.
8. Add the somewhat cooled rhubarb mixture over the top of cake batter (see pictures for reference).
9. Optional: If you like, sprinkle the top with a cinnamon/sugar mix before baking.
10. DO NOT MIX. Just leave it in the two layers and let the oven do the work.
11. Bake for 40 minutes. When the cake is done, a toothpick inserted into the centre will come out clean.
12. Let cool.
13. You can serve this dessert warm with vanilla ice cream!