Step 1: Prepare the Cake Batter

1. Preheat the Oven: Set your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan or line it with parchment paper for easy removal.
2. Mix Wet Ingredients: In a large bowl, cream together the softened butter and granulated sugar until light and fluffy, about 2-3 minutes.
3. Add the eggs, one at a time, mixing well after each addition.
4. Stir in the sweet potato puree and vanilla extract until the mixture is smooth.
5. Combine Dry Ingredients: In a separate bowl, whisk together the flour, baking powder, and salt.
6. Combine Wet and Dry Mixtures: Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk. Begin and end with the dry ingredients. Mix until just combined; avoid overmixing.

Step 2: Bake the Cake

1. Pour the Batter: Transfer the batter to the prepared baking pan, smoothing the top with a spatula.
2. Bake: Place in the preheated oven and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.
3. Cool: Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

Step 3: Make the Pecan Praline Glaze

1. Prepare the Glaze: In a medium saucepan over medium heat, combine the brown sugar, butter, and heavy cream. Stir constantly until the mixture comes to a boil.
2. Let it boil for 1-2 minutes without stirring.
3. Remove from heat and stir in the chopped pecans and vanilla extract.

Step 4: Glaze the Cake

1. Once the cake has cooled completely, pour the pecan praline glaze over the top, allowing it to drip down the sides for a beautiful finish.
2. Let the glaze set slightly before slicing and serving.