Preheat your oven to 350°F (175°C). Grease and line your cake pans with parchment paper.
In a medium bowl, whisk together flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
In a large bowl, beat eggs and sugar until fluffy and light in color. Gradually add oil, yogurt, and vanilla, mixing until well combined.
Stir in the dry ingredients until just combined. Fold in carrots, pineapple, walnuts, and raisins.
Divide the batter evenly between the prepared pans. Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean.
Allow the cakes to cool in the pans for 10 minutes, then turn out onto a wire rack to cool completely.
For the frosting, beat butter and cream cheese until smooth. Gradually add powdered sugar and vanilla, beating until creamy.
Once the cakes are cool, level them with a knife if needed. Spread frosting on the first layer, add the second layer on top, and frost the outside of the cake.
Garnish with additional chopped walnuts.