Place a rack in the upper third if the oven and preheat to 200 degrees F. This will keep the pancakes warm as they’re baked in batches.
To make the pancakes: in a large bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, nutmeg, ginger, and, if desired, nuts and raisins.
In a small bowl, whisk together egg, brown sugar, buttermilk, and vanilla. Stir in the carrots.
Pour the buttermilk mixture, all at once, into the flour mixture and stir until just incorporated. Let rest for 5 minutes while you make the cream cheese spread.
To make the cream cheese spread: in a small bowl, whisk the cream cheese until soft and pliable and no lumps remain. Whisk in powdered sugar, milk, vanilla, and cinnamon. If you’d like a thinner consistency, add a dash more milk. Set aside to top the pancakes.
Over medium heat, melt 1 tablespoon of the butter in a cast-iron skillet or griddle pan. Spoon 2 tablespoons batter into the hot pan and cook, flipping once, until pancakes are golden on both sides, about 2 minutes per side.
Place pancakes on an ovenproof plate and store in the oven while you cook the rest of the pancakes, adding more butter to the griddle as needed. Serve warm with cream-cheese spread. Pancakes are best served immediately.