• Preheat your oven to 350°F.
• Grease and flour two 9-inch round cake pans or a 9×13 pan.
• If you’re making your own buttermilk, mix the milk and vinegar and let it sit for at least 5 minutes.
• Sift the Einkorn flour, baking powder, baking soda, and salt into a medium bowl. Set aside.
• Make Chocolate Mixture: Whisk the melted butter and cacao powder in a small bowl or saucepan until smooth. Set this mixture aside to cool to room temperature.
• Cream Eggs & Sugar: In a large bowl, beat the sugar and eggs together at medium speed on your electric mixer for at least 5 minutes, until pale and fluffy.

  This step is crucial for creating a light, airy texture in the cake.
• Combine Chocolate Mix and Creamed Eggs & Sugar: Slowly whisk the Chocolate Misture into the Creamed Eggs & Sugar Mix until fully incorporated and smooth.
• Mix Remaining Wet Ingredients: Whisk together the buttermilk (or milk and apple cider vinegar), water, and vanilla extract. Make sure all wet ingredients are thoroughly combined.
• Gradually stir the Remaining Wet Ingredients Mixture into the Chocolate + Creamed Eggs & Sugar Mix.
• Finish the batter by gently adding the sifted Einkorn and dry ingredients to the wet mixture, stirring gently until combined.

  Be careful not to overmix, as Einkorn’s gluten is more delicate than modern wheat, and overmixing can lead to a dense cake.
• Preparing to Bake:

  For a Double-Layer Cake, Evenly divide the batter between two prepared 9-inch round cake pans.

  For a 9×13-inch Cake, Pour all the batter into a prepared 9×13-inch cake pan.

  Once the batter is in the pan(s), gently lift each pan slightly off your countertop and give it a firm bang to remove any air pockets.
• Bake the 9-inch pans for 25-30 minutes. A toothpick inserted into the center should come out clean or with a few moist crumbs.

  For a 9×13 cake: Bake for 30-35 minutes, starting to check for doneness at the 30-minute mark using a toothpick test.

  If using a dark pan, reduce the bake times slightly; if using glass or ceramic, you may need to bake a bit longer.
• When the cake is done baking, remove it from the oven and let it cool in the pan on a wire rack for 10 minutes. Then, carefully remove the cake from the pan and place it on the rack to cool completely.
• If you plan on serving the 9×13 cake directly from the pan, let it cool completely in the pan before frosting and serving.

Assembling The Cake

• Make sure the cake layers are completely cooled before frosting.
• Place the first layer on your cake plate.
• Using a spatula, spread 1/2 to 3/4 cup of frosting evenly over the top.
• Add the second layer and spread the remaining frosting over the top and sides of the cake, covering it completely.

Instructions for Buttercream Frosting

• Place the softened butter in a large bowl. (To save on cleanup, you can rinse and reuse the bowl you used for making the cake batter.)
• Beat the butter with an electric mixer on high speed for 10 minutes until it’s light and fluffy.

  I know this seems like a long time, but I just turn on my mixer and work on something else. The longer you beat it, the better the frosting – I promise!
• Gradually add the sugar, 1/2 cup at a time, while continuing to mix on high speed.
• Scrape down the sides of the bowl often to ensure everything is well incorporated.
• If the mixture starts to clump, add a small amount of water (or milk/cream) and continue adding the sugar.

  Be careful when adding the sugar to avoid it flying all over your kitchen—adding it slowly will help.
• Once all the sugar is added, mix in the vanilla and any remaining water (or milk/cream) a little at a time until you reach the desired consistency.
• For thinner frosting, add more liquid in small amounts (1/8 teaspoon at a time).

  For thicker frosting, stop adding liquid once the consistency is right.
• Now add the cacao powder, one tablespoon at a time, until it’s thoroughly mixed in.

  You can adjust the amount of cacao to get the chocolate flavor you want.

  If you prefer vanilla frosting, leave out the cacao powder.