Preheat the oven to 350 degrees. Place desired cupcake wrappers in the muffin tins. Whisk the flour and baking soda together in a medium-sized bowl. Add the peanut butter, vegetable oil, honey, carrots and egg to the flour mixture. Use a spatula to mix until combined. Scoop the batter into the wrappers, until about 3/4 full. Cook for 25-30 minutes, or until a knife comes out clean. Allow the pupcakes to cool before “frosting” with additional peanut butter. Garnish with dog treats, if desired. The pupcakes, minus the peanut butter frosting, can be stored in the freezer. Bring the pupcake to room temperature before frosting.