1cupfinely diced sweet appleabout 1 medium size apple
Preheat oven to 350 °F. Spray a mini muffin pan with nonstick cooking spray or line with mini muffin papers.
In a mixer on medium speed, cream together butter and pumpkin, about 3-4 minutes.
Add brown sugar and continue to beat in for about 3 minutes. Then add honey and mix until well combined.
Stop mixer and add in egg and vanilla. Mix on low speed until well combined.
Stop mixer and add in flour, baking soda, cinnamon, nutmeg, and salt. (You may need to add flour in 2 batches depending on the size of your mixing bowl.) Mix in on low speed until incorporated, then add ground flax seed and increase speed slightly and mix well for one minute or less.
Toss in diced apple and fold into batter using a spatula.
Spoon into muffin pan, about 1 tablespoon of batter per opening. (Fill about 75% full.)
Bake for 10 minutes or until toothpick inserted into the center of a muffin comes out clean.
Let cool in pan for 2 minutes, then remove and cool on a wire rack.
You can substitute 1 ¼ teaspoon of pumpkin pie spice for the cinnamon and nutmeg if you prefer.