Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan.
In a mixing bowl, cream the softened butter and sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition.
Stir in the vanilla extract and mix until combined.
In a separate bowl, whisk together the flour, baking powder, cinnamon, and salt.
Gradually add the dry ingredients to the wet mixture, alternating with the milk.
Mix until just combined; do not overmix.
Pour half of the batter into the prepared pan and sprinkle with nuts, if using.
Add the remaining batter on top and smooth the surface.
Bake in the preheated oven for 30-35 minutes or until a toothpick inserted in the center comes out clean.