Preheat your oven to 350°F (175°C). In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy. Beat in the eggs, one at a time, then stir in the vanilla extract.
In another bowl, whisk together the flour, baking powder, and ground cinnamon. Gradually add this mixture to the wet ingredients, alternating with the milk, and mix until just combined.
Pour half of the batter into a greased baking pan. Sprinkle a mixture of brown sugar and cinnamon over the batter, then add the rest of the batter on top, smoothing it out.
Bake in the preheated oven for about 30 minutes or until a toothpick inserted into the center comes out clean.
Allow the coffee cake to cool for a few minutes before slicing and serving. Enjoy it warm with your favorite coffee!
Notes
This coffee cake can be enjoyed as a snack or a sweet breakfast treat. Feel free to add nuts or fruit for extra flavor!