Preheat your oven to 375°F (190°C). Peel and chop sweet potatoes into chunks. Boil in salted water until tender, about 15-20 minutes. Drain and mash until smooth. Allow to cool.

In a large mixing bowl, cream together the softened butter and granulated sugar using an electric mixer on medium speed until light and fluffy, about 3-5 minutes. This helps to incorporate air into the batter for a lighter cake.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In a separate bowl, whisk together the sifted flour, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet mixture, mixing on low speed until just combined. Be careful not to overmix, as this can lead to a dense cake.

Fold in the mashed sweet potatoes and chopped pecans using a rubber spatula until evenly distributed.

Grease and flour a 9x5 inch loaf pan. Pour the batter into the prepared pan, smoothing the top with a spatula.

Bake in the preheated oven for 55-65 minutes, or until a toothpick inserted into the center comes out clean. The cake should be golden brown and spring back when lightly pressed.

Once baked, remove from the oven and let the cake cool in the pan for 10 minutes. Then, transfer to a cooling rack to cool completely.

In a small bowl, whisk together the powdered sugar, milk, and vanilla extract until smooth. Adjust the milk quantity for desired consistency.

Drizzle the glaze over the cooled cake before slicing and serving.