Preheat oven to 350 degrees F. Lightly oil or spray with a nonstick spray an 8x8-inch baking pan and set aside.
In a small bowl, stir together all the topping ingredients, using the back of a fork to separate the butter and incorporate it throughout.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon.
Stir in the yogurt, milk of choice, brown rice syrup, and vanilla. Mix everything completely until just combined. You will have a very thick dough.
Spoon it into baking pan evenly and sprinkle topping over the top.
Bake for 30-35 minutes, until a toothpick inserted in the middle of the cake comes out clean.