Prepare the Cake

Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan or line it with parchment paper.

In a large mixing bowl, whisk together the flour, sugar, baking powder, baking soda, salt, and cinnamon (if using).

In a separate bowl, beat the softened butter until smooth. Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract.

Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk. Start and finish with the dry ingredients. Mix until just combined; be careful not to overmix.

Pour the batter into the prepared cake pan and smooth the top with a spatula.

Bake the Cake

Bake for 30-35 minutes, or until a toothpick inserted into the center of the cake comes out clean.

Remove the cake from the oven and let it cool in the pan for 10 minutes, then transfer it to a cooling rack to cool completely.

Prepare the Glaze

In a small saucepan, heat the milk over low heat until warm (do not boil). Stir in the powdered sugar and vanilla extract until the glaze is smooth and fully combined.

Once the cake has cooled, drizzle the glaze evenly over the top of the cake, allowing it to drip down the sides. You can also add a little extra glaze if you prefer a thicker layer.