Preheat your oven to 350°F (175°C). Line your muffin tins with paper liners or lightly grease them to prevent sticking. This ensures your muffins come out easily after baking.

In a medium-sized mixing bowl, whisk together the pumpkin puree, eggs, and pumpkin pie spice blend until smooth and well combined.

Add the yellow cake mix to the pumpkin mixture. Use a hand mixer to whip everything together for about 2 minutes until the batter is fluffy and completely blended. I find using a hand mixer really helps get a light, airy texture.

Pour the batter into the prepared muffin tins, filling each about ¾ full. Evenly top each muffin with pieces of salted butter, a sprinkle of brown sugar, and coarse sparkling sugar. This topping adds a delicious crunchy and buttery finish.

Bake the muffins in the preheated oven for 30 minutes until a toothpick inserted comes out clean. Let them rest in the muffin tin for 5 minutes before serving. For an extra touch, I like to serve them warm for the best flavor and texture.