Preheat the oven to 350 degrees F.
Line the bottom of three 6-inch round cake pans or two 8-inch round cake pans with parchment paper rounds. Spray parchment paper and sides of the pans with nonstick cooking spray. YOU SHOULD USE PARCHMENT PAPER or the cake is likely to stick. Please do not forget.
In a large bowl, whisk together the eggs, honey, yogurt, lemon zest, lemon juice and almond extract. The mixture should be smooth and well combined.
In a separate bowl, whisk the almond flour, oat flour, poppy seeds, baking soda and salt. Add the dry ingredients to the wet ingredients and mix well with a rubber spatula until smooth.
Divide batter evenly between pans and spread out with a spatula to smooth the tops. Bake for 18-28 minutes in the two 8-inch pans or 25-35 minutes for three 6-inch pans. Cakes are done when a tester comes out clean or with just a few crumbs attached. Allow the cake to cool completely before frosting or removing from the pans. The cake should be room temperature when you frost it. This is very important. Cakes can be made a day ahead if you’d like.
Make your frosting: Add ½ cup raspberries to a blender and blend until smooth. Pour mixture through a sieve over a small bowl and use the back of a spoon to get all of the juice out so you only have the seeds remaining. Set the raspberry juice puree aside. In the bowl of an electric mixer, add the softened butter or vegan butter and whip on high until light and fluffy, about 1-2 minutes. Add 4 cups powdered sugar, lemon juice, lemon zest and 2 tablespoons of the raspberry puree; beat on high for 1-2 minutes more until well combined. Taste and add more powdered sugar to your liking, if necessary. You may need to scrape the frosting down the sides of the bowl and then beat again. Optional: You may need to add in a little bit of milk (about 1 tablespoon) to thin the frosting out so it’s a little more creamy, but it depends on how you like it! I love a thick frosting.
Now it’s time to frost the cake: place about 1 tablespoon down onto the cake stand and spread out. Invert a cake onto the cake stand, add about ½ heaping cup frosting between each layer. Cut the raspberries reserved for the filling in half lengthwise, and place them over the filling between each layer, covering the entire surface. You want to sort of smoosh them into the frosting as best you can. It’s okay if they break a bit, but it is important that they are well nestled into the frosting so that there aren’t large gaps between the cake layers. Repeat with each cake, then frost the top and sides of the cake with the remaining lemon frosting. If the cake is slightly ‘naked’ on the outside, that’s okay, it’s going to be delicious!
Garnish with fresh raspberries just before serving the cake to make sure they stay as fresh as possible!
Cake will stay good at room temp for a day or so, then should be placed in the fridge. Cake will stay good for 5-7 days in the fridge, and should be well-covered to ensure freshness.