Butter & Brown Sugar Rhubarb Cake

This is a cake my mother made early in the summer when rhubarb was in season. She froze a piece to save for me, which I had today. The cake is moist and tasty and seems easy to make. She used fresh rhubarb from our garden.

Butter & Brown Sugar Rhubarb Cake
CAKE
1 cup butter, softened
1 cup packed light brown sugar
3 large eggs
1 teaspoon vanilla extract
1 cup plain Greek yogurt
2 cups all-purpose (plain) flour
1 Tablespoon baking powder
1/4 teaspoon salt
3/4 cup diced fresh rhubarb coated in a little flour
TOPPING
1/2 cup diced fresh rhubarb
1/4 cup granulated (white) sugar
1/2 teaspoon ground cinnamon

Preheat oven to 350◦F. Line a 9x13 inch rectangular pan with parchment paper.
CAKE: In a large bowl, cream together the butter and brown sugar until light and fluffy. Beat in the eggs, one at a time. Mix in the baking powder, salt, and a third of the flour, then half the yogurt, another third of flour, the remaining yogurt, then the remaining flour. Fold in the rhubarb. Spread evenly in prepared pan.
TOPPING: Mix all together and scatter over batter in pan. Bake for 20-30 minutes until a wooden toothpick inserted in the center comes out clean.