Preheat the oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners and lightly spray or brush them with olive oil.

In a large bowl, combine the spice cake mix, pumpkin puree, milk, eggs, olive oil, and pumpkin pie spice. Mix with a hand mixer or stand mixer until just combined. Do not overmix.

If using, fold in chopped nuts or chocolate chips.

Scoop the batter into the prepared muffin liners, filling each about 3/4 full. If desired, sprinkle a little sugar or monk fruit sweetener on top of each muffin.

Bake for 18–22 minutes, or until a toothpick inserted in the center comes out clean. Let cool in the pan for 5–10 minutes before transferring to a wire rack to cool completely.

For the optional maple glaze, whisk together powdered sugar and maple syrup. Add a small amount of milk as needed until the glaze reaches a smooth, drizzle-able consistency. Drizzle over cooled muffins and let set before serving.