Preheat oven to 350 degrees. Cut a circle out of parchment paper to line the bottom of an 8 or 9-inch round cake pan. Lightly grease the pan and set aside.: The warm scent of the oven as it comes up to 350 degrees is reassuring, and lining the pan with parchment prevents the cake from sticking to the bottom when you invert it. You should feel the anticipation as the kitchen warms and the batter will bake evenly once the oven reaches temperature. A common mistake here is skipping the parchment or not greasing the pan, which can tear the cake when you remove it, so take the extra minute to prepare the pan carefully. Visually, the pan should look evenly coated, and the parchment circle should sit flat, preventing bubbles that could imprint the cake bottom.
In a large bowl, whip coconut oil (or butter if you choose) with sugar until light and fluffy. Stir in eggs, vanilla, and lemon zest. Scrape sides and whip again. Alternate mixing in flours with milk. Scrape sides and mix until all ingredients are incorporated.: At this stage you will notice the aroma of lemon and vanilla blooming as the sugar and fat aerate, which helps trap tiny air pockets that give the cake lift. The texture of the batter should go from gritty to glossy as the sugar dissolves into the fat, and when the eggs are added the batter becomes smoother and slightly more elastic. Alternating the flours with the milk encourages gentle incorporation so the gluten does not develop unevenly, preserving tenderness. If you overmix after the flours are added you may create a dense crumb, so stop mixing as soon as the streaks disappear. A troubleshooting tip is to scrape the bowl thoroughly between additions to ensure no pockets of dry flour remain, which would produce dry spots in the cake.
Spoon into prepared pan, smooth the top and bake 30-40 minutes or until a toothpick comes out clean when inserted. Cool 15 minutes and then remove the cake from pan. Cool completely before frosting.: You will hear the oven hum and the batter set as steam escapes, and the top will develop a pale golden color. The toothpick test is the safest indicator of doneness, and the center should spring back gently when pressed, not sink. Cooling 15 minutes before removing from the pan allows the crumb to stabilize so it does not collapse, and finishing the cool on a wire rack prevents the bottom from becoming soggy. A common error is slicing into the cake too soon, which can ruin its structure, so be patient until the cake is fully cool for the best frosting surface.
Whip cream cheese in a stand mixer to soften. Slowly stream in cream to incorporate evenly. If lumps start to form, stop mixing, scrape sides, and continue to mix. Once all cream is incorporated, the mixture should seem thick and smooth.: As you whip the cream cheese , you should notice it loosening and becoming glossy, and streaming in the cold heavy whipping cream helps create a lighter, scoopable frosting base. If lumps appear, it usually means your cream cheese was too cold, so pausing and scraping the sides helps bring everything to one temperature and restores a smooth texture. The mixture should be thick enough to mound but not runny, which ensures it will hold the raspberries on top. Avoid working the mixture excessively at high speed if it starts to separate, and instead reduce speed and scrape frequently to maintain a uniform emulsion.
Stir in remaining ingredients and stir to incorporate. Once frosting seems smooth, turn the mixer on high and whip 2-3 minutes or until fluffy and light, similar to whipped cream but a little heavier.: When you add the powdered sugar , additional lemon zest, and vanilla , the frosting becomes sweeter and more aromatic, and whipping at the end brings air in so it feels cloudlike yet substantial. The texture should be smooth, with soft peaks forming as you lift the beater. That extra whipping time improves spreadability and creates a tidy finish on the cake, but overwhipping can make the frosting too loose. If it loosens, chilling briefly will help it firm up before spreading. Smell for that clean lemon note which signals balance between tang and sweetness.
Spread all frosting over cooled cake and top with lots of fresh raspberries. Store in refrigerator until ready to serve.: As you spread the frosting, you will feel a satisfying drag of the spatula across a smooth surface, and the contrast of the pale frosting with the vivid raspberries is visually appealing. Press the berries in slightly so they do not roll off, arranging them in a single layer or a casual cluster, depending on the look you want. Refrigerating the cake helps the frosting set and keeps the raspberries fresh, but be aware that very long storage can soften the berries and slightly moisten the top. A common misstep is leaving the cake at room temperature for too long, which can make the frosting soft and the berries wilt, so keep it chilled until serving for the best presentation and texture.