to make the cake: 

1. Preheat your oven to 350°F / 180° C and make sure your middle rack is in position. Butter three 8" cake pans lining the bottoms with parchment paper, so the parchment paper sticks to the pan. Butter the top of the parchment paper too, and dust with either flour or cocoa powder. I used cocoa powder. Don't skip this part! :)
2. Make your ¾ cup of coffee and let it cool. I just use hot water and add a heaping teaspoon of high quality instant coffee. You can find instant coffee pretty much anywhere, but as of lately, I use a Trader Joe's brand.
3. In an electric mixer, using the paddle attachment, stir together all of your dry ingredients: sugar, flour, cocoa powder, baking powder and salt.
4. In a separate medium sized bowl, whisk together all of your wet ingredients: buttermilk, sunflower oil, yogurt or sour cream, eggs, vanilla and coffee. Make sure all of these ingredients are room temperature before combining. (You don't want the hot coffee to scramble your eggs.) 
5. Slowly pour your liquid mixture into your dry ingredients, keeping the speed on low. Mix for about 30 seconds, then scrape down your bowl once or twice to ensure the bottom is getting mixed in.
6. Mix for about 1 minute or a minute and a half or until all the ingredients are mixed and incorporated. Batter will be very thin.
7. Evenly distribute your batter among your three greased and prepared tins and bake for 20-25 minutes. The center of the cake should not look wet, and spring back ever so slightly if you press your finger to the top. Remember that the cakes will still cook a tiny bit more when they're pulled out of the oven and left in their tins.
8. Cool cakes for 15 minutes, then take them out of their cake tins and let them finish cooling on a cooling rack.

to make the raspberry buttercream:

1. bakers note: I know they say baking is an exact science but to me 90% of it is intuitive. Use your gut. The original recipe calls for only 5 egg whites but adding 1 more egg white worked better for me. It's dry here in Utah, and I'm at a high altitude, I'm guessing that had something to do with it. Don't stress too much about it. You want your egg whites + sugar mixture to be a wet and snotty (sorry) consistency. If it seems like it's too thick with sugar (aka not a snot consistency), add more egg white. 
2. Using either an immersion blender or a potato masher, smash your fresh raspberries and then strain them through a fine mesh sieve to remove all of the seeds. Set this beautiful liquid aside.
3. Fill a medium sized saucepan with a little bit of water (about 2-3 inches). The saucepan needs to be big enough to place a glass bowl on top, but make sure the bowl does NOT touch the water.
4. Put egg whites and sugar in the glass bowl (or other heat proof bowl)  that will fit over your medium sized saucepan.
5. Bring the water in the medium sized saucepan to a gentle simmer. Place the glass bowl on top of the saucepan and whisk gently for about 8-10 minutes, or until mixture becomes 160°F / 71°C. You'll know it's ready because the mixture should be too hot to hold your finger in the mixture for a long time, but not too hot to touch.
6. Remove egg white mixture from the heat and pour into your electric mixing bowl. Add salt. With the whisk attachment, whisk heated egg whites and sugar until it looks like a stiff cloud or shaving cream. The mixture should cool as it whips, and the outside of the bowl should feel room temperature. This takes about 5-10 minutes.
7. Switch to a paddle attachment.
8. On a medium speed, add the butter 1 tablespoon at a time, until the butter is fully incorporated, scraping the bowl about halfway.
9. Buttercream should be light and fluffy and free of any butter clumps. If you have butter clumps it simply means your butter was a little too cold when you added it into your meringue, give it some times to soften - and then try beating it again.
10. Next slowly stream in your raspberry puree. You can beat this in by hand, pouring the puree in little by little or using the electric mixer. Mix until incorporated. tip! You can easily store the frosting in the fridge at this point and then whip it back to room temperature in your electric mixer. See bakers note* at the beginning of the recipe. 
11. Make sure your cakes have cooled completely before frosting.
12. Frost and top cake with fresh raspberries and cocoa nibs or any decoration of your choice. I think the cake keeps pretty well for 3 days in the fridge, but tastes best the day of or the day after it's made. xo