Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish.

In a large mixing bowl, whisk together the flour, sugar, baking powder, salt, and ground cinnamon.

Add in the melted butter, milk, eggs, and vanilla extract. Mix until just combined; it's okay if there are a few lumps.

Spread half of the batter evenly into the prepared baking dish.

In a separate bowl, mix the brown sugar and cinnamon together for the filling and sprinkle this mixture over the batter.

If using pecans, add them at this stage.

Dollop the remaining batter on top and gently swirl it together with a knife.

Bake for about 25-30 minutes or until a toothpick inserted into the center comes out clean.

While the cake is cooling, prepare the cream cheese glaze.

In a medium bowl, beat the softened cream cheese until smooth, then gradually add in the powdered sugar, milk, and vanilla extract, mixing until smooth.

Drizzle the glaze generously over the cooled cake and enjoy.