First, cream the butter with granulated and brown sugar until fluffy. Then, add the eggs and vanilla, mixing just until incorporated. Carefully fold in the dry ingredients and oats without overmixing to keep cookies soft.
Gently fold in the grated carrots and optional walnuts. I always make sure the carrots are well-packed in the measuring cup for accurate measurement. The mixture should be thick but scoopable.
Preheat your oven to 350°F (175°C). Use a cookie scoop to drop even portions onto a parchment-lined sheet. Bake for 12-15 minutes until golden brown, then cool completely on a wire rack. Patience is key; warm cookies will melt the frosting.
Beat softened cream cheese and butter until smooth, then gradually add powdered sugar and vanilla. The frosting should be thick yet spreadable. I like to taste a tiny bit – it’s irresistible!
Pair similar-sized cookies and place a generous tablespoon of frosting on one. Gently press the other cookie on top, spreading frosting to the edges. For a neat look, don’t overfill, and I always wipe extra frosting off the sides with a spatula