Preheat the oven to 375 degrees F. Line a muffin pan with paper baking cups. Spray the inside of the cups with cooking oil.
In a medium bowl combine all the dry ingredients and set aside.
In a food processor with the shredder blade, shred 2-3 carrots. Alternatively, you can shred by hand until you have 1 rounded cup. Combine carrots with the rest of the wet ingredients. Mix the dry ingredients into the wet. Fold in walnuts.
Scoop batter into prepared baking cups, filling each on to the top. Top with more walnuts if desired.
Bake for 20 minutes, until a knife inserted in the middle comes out clean. Let cool on a cooling rack for 10 minutes before serving.
Store in an airtight container at room temperature for up to 5 days or in the freezer for 1 month.