• Preheat oven to 350°F. Line a 10×15-inch sheet pan (jelly roll pan) with parchment paper.
• To the bowl of a stand mixer fitted with the paddle attachment, add sugar, oil, vanilla extract, and eggs. Mix on medium speed until the mixture is light yellow and slightly thickened, about 3 minutes.
• To a medium mixing bowl, add all-purpose flour, ground cinnamon, ground nutmeg, baking soda, and kosher salt. Whisk to combine.
• With the mixer on low speed, gradually add the dry ingredients to the wet ingredients. Mix until just combined, being careful not to over-mix.
• Remove the bowl from the stand mixer. Gently fold in the chopped walnuts, grated carrots, and drained pineapple. Mix until the ingredients are evenly distributed throughout the batter.
• Pour the batter into the prepared pan, spreading it evenly to ensure it bakes uniformly. Bake for 24-28 minutes. Begin checking at the 22-minute mark by inserting a toothpick into the center. If it comes out with a few moist crumbs (but not wet batter), the cake is ready.
• Once done, remove the cake from the oven and let it cool completely before frosting.

Maple Frosting

• To a large bowl, add the butter, maple syrup, and maple extract. Using a hand mixer or stand mixer fitted with the paddle attachment, beat on medium speed until the mixture is smooth and creamy.
• Gradually add the confectioners' sugar, about ½ cup at a time, mixing well after each addition. Continue adding sugar until the frosting reaches a thick and creamy consistency. Adjust the amount of sugar based on your desired sweetness and creaminess level.
• Once the cake is completely cool, spread a thick, even layer of the maple frosting over the top. Smooth with a spatula. Or, if preferred, pipe decorative swirls for a special touch.
• Sprinkle with chopped walnuts for garnish (optional). Cut and serve.