Preheat the oven to 350°F and line a glass 8x8 baking pan with parchment paper.
In a large mixing bowl, whisk together eggs and sugar. Add in butter, greek yogurt and vanilla extract and mix until smooth. Add in flour, baking powder, baking soda, and salt. Mix until well combined.
In a separate bowl, mix together brown sugar, butter and cinnamon.
Add half of the batter into the lined baking pan. The dough is very sticky and the best way to evenly spread it is by adding a little flour to your hands.
Spread half of the cinnamon sugar filling evenly across the bottom layer.
Add the remaining dough and spread evenly.
Mix in the flour to the remaining cinnamon sugar mixture. Mix until it forms small balls/crumbles. Add to the top of the dough.
Bake for 40-45 minutes, or until a toothpick comes out mostly clean.