How to Make It
Make the cake: Preheat oven to 350°F. Line an 8-inch square metal baking pan with parchment paper, allowing paper to overhang about 2 inches.
Whisk together flours, cinnamon, baking soda, and salt in a medium bowl. Make a well in center of mixture; crack in eggs, and whisk to beat. Add buttermilk, honey, and vanilla; whisk until well blended. Fold in carrots and 1/2 cup pecans. Spoon mixture into prepared baking pan.
Bake in preheated oven until a wooden pick comes out with a few moist crumbs clinging, 25to 27minutes. Let cool in pan on a wire rack 5 minutes. Remove cake from panusing parchment as handles, and let cool on rack to room temperature, about 1 hour.
Make the frosting: Combine cream cheese and butter in a large bowl; beat with a handheld mixer on medium speed until fluffy, about 1 minute. Addvanilla and salt; beat just until combined. Add powdered sugar; beat on low speed until just combined; increase speed to medium, and beat until smooth. Spread frosting over cake. Sprinkle with remaining 1/4 cup pecans. Store in refrigerator for up to 1 week.