"My daughter and I developed this recipe because we couldn't find one we liked. We prefer straight carrot cake, ie no raisins, nuts, or other add-ins other than shredded carrots. This was developed at 6,000 feet altitude; see notes for possible baking adjustments at a lower altitude."
Preheat oven to 350 degrees F (175 degrees C). Line muffin tins with paper liners and spray liners with vegetable oil spray to prevent cupcakes from sticking to liners.
Combine flour, cinnamon, salt, baking soda, baking powder, allspice, and ginger in the bowl of a food processor; mix to incorporate ingredients, 5 to 10 seconds. Transfer to a bowl and toss in shredded carrots.
Use the food processor to combine white sugar, brown sugar, eggs, buttermilk, and vanilla extract with a paddle attachment. Drizzle in the vegetable oil while the food processor is still running. Add to flour mixture and mix just until combined.
Scoop batter into the prepared muffin tins to fill the cups 2/3 full.
Bake in the preheated oven until tops spring back when lightly pressed, 17 to 20 minutes. Cool in the pan for 5 minutes before transferring to a wire rack to cool, about 20 minutes.
Beat cream cheese and butter together with the paddle attachment of a stand mixer on medium speed. Stir in vanilla extract. Add confectioners' sugar gradually on low speed; turn to high speed and mix until smooth and creamy.
This cupcake recipe was developed at high altitude (6,000 feet). At a lower altitude you may need to try adding only 2 cups flour in the beginning to ensure your batter is not too thick and cupcakes are not too dry and dense. If batter is too loose and wet with 2 cups flour, add flour 1/4 cup at a time and incorporate to thicken. Test bake 1 cupcake to determine correct amount of flour for your altitude. If the cupcake sinks in the middle, add 1/4 cup more flour to the batter. At a lower altitude, cooking time may be longer than 20 minutes.
When incorporating confectioners' sugar to creamed butter and cream cheese, place a kitchen towel over the stand mixer before turning mixer on to prevent sugar dust from blowing all over. Once incorporated, you can remove the towel.
In place of vegetable oil, you may use any oil of your choice, such as canola or coconut oil.
If you like a lot of frosting on your cupcakes, double the frosting recipe.