Preheat your oven to 350°F (175°C). Line your baking pan with parchment paper.
This prevents sticking and makes cleanup easy. Set the pan aside for later use.
Beat softened butter and sugar until fluffy. This takes about 3 minutes with a mixer.
Add eggs one at a time, mixing well. Pour in vanilla extract and mix thoroughly.
The mixture should look light and creamy.
In another bowl, combine flour and salt. Gradually add this to the wet mixture.
Mix until just combined, don't overmix. The batter should be thick and smooth.
Pour the batter into your prepared pan. Use a spatula to spread it evenly.
Make sure it reaches all corners. The layer should be uniform in thickness.
Mix sugar and cinnamon in a small bowl. Drizzle melted butter over the batter.
Sprinkle the cinnamon-sugar mixture generously on top. Cover the entire surface evenly.
Place the pan in your preheated oven. Bake for 25-30 minutes until golden brown.
A toothpick inserted should come out clean. Let it cool for 15 minutes.
Cut into squares once cooled slightly. Serve warm or at room temperature.
Enjoy with your favorite beverage!