Position oven rack just below center of oven. (See Note.) Preheat oven to 325°F (170°C). Spray an 8½x4½-inch loaf pan with cooking spray. Line with parchment paper, letting excess extend over sides of pan.
In the bowl of a stand mixer fitted with the paddle attachment, beat butter, sugar, and orange zest at medium speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs, one at a time, beating until well combined after each addition.
In a medium bowl, whisk together flour, salt, and baking soda. In a small bowl, whisk together sour cream and vanilla. With mixer on low speed, gradually add flour mixture to butter mixture alternately with sour cream mixture, beginning and ending with flour mixture, beating just until combined after each addition and stopping to scrape sides of bowl. Spoon batter into prepared pan, smoothing top with a small offset spatula. Tap pan on a kitchen towel-lined counter several times to settle batter and release any air bubbles.
Bake until a wooden pick inserted in center comes out clean, 55 minutes to 1 hour and 6 minutes, loosely covering with foil after 45 minutes of baking to prevent excess browning. Let cool in pan for 10 minutes. Using excess parchment as handles, remove from pan, and let cool completely on a wire rack.
Using a serrated knife or a cake leveler, cut cake in half horizontally. Using a small offset spatula, spread preserves onto bottom half; place top half, cut side down, on top of preserves. Wipe away any excess preserves from sides of cake.
Place cake on a wire rack set over a parchment paper-lined baking sheet. Gradually pour and spread Chocolate Glaze onto cake, using a small offset spatula to spread on top and coat sides. Place another sheet of parchment under wire rack. Once excess has dripped off but glaze is still wet, cover cake evenly on all sides with coconut. Let stand until glaze is set, about 30 minutes.
Notes
The cake can also be baked in the center of the oven, if desired, but it will have a more rounded top.
Recipe by Bake from Scratch at https://staging.bakefromscratch.com/orange-plum-lamington-loaf-cake/