In a saucepan over medium heat, melt ½ cup butter. Cook for 2–3 minutes until the mixture is smooth and begins to bubble. Pour the pecan mixture evenly into the bottom of your prepared cake pan.

In a medium bowl, whisk together flour, baking powder, and salt. Set aside. In a large bowl, cream ¾ cup softened butter and ¾ cup granulated sugar using a mixer until light and fluffy. Add eggs one at a time, beating well after each addition. Stir in vanilla extract. Mix in the dry ingredients alternately with the milk until just combined.

In a separate bowl, prepare the boxed yellow cake mix using the package directions (usually mixing the cake mix with 1 cup water, ½ cup oil, and eggs if not already included). Fold your homemade cake batter into the prepared cake mix for extra moisture and richness.

Pour the combined cake batter gently over the pecan topping in the pan. Spread evenly. Bake in a preheated oven at 350°F (175°C) for 40–45 minutes, or until a toothpick inserted in the center comes out clean.

Let the cake cool in the pan for 5–10 minutes. Carefully invert onto a serving plate while still warm so the pecan topping is on top. Serve warm or at room temperature.