Preheat the oven to 350°F (175°C). Line the baking pan with parchment paper for easy removal.
In a large mixing bowl, use a rubber spatula or electric mixer to cream together the softened butter and sugar until the mixture appears fluffy and pale, about 2-3 minutes. Watch for a light, airy texture with slight volume increase.
Add the eggs one at a time, mixing well after each addition. The mixture should become smooth and slightly thickened, with a glossy appearance. Add vanilla extract and mix until combined.
Gradually incorporate the sifted flour into the wet ingredients, mixing on low speed or folding with a spatula until just combined. The dough should be thick and hold together when pressed.
Press the dough evenly into the prepared baking pan with your hands or a spatula, ensuring a smooth, level surface. The dough should be about 1/2 inch thick and uniformly distributed.
Bake in the preheated oven for 20 minutes, or until the edges are golden brown and a toothpick inserted in the center comes out clean. The top should be set and lightly crisp.