Preheat an oven to 350 degrees F (180C) or 325 F (160C) for a convection oven. Grease 3 8-inch cake pans with baker's floured spray (or line with parchment rounds).

Pour in eggs and mix on low until just combined. Whisk together sourdough discard and milk until well-combined. Add the sourdough discard/milk mixture in 2 parts, mixing until combined.

Add vanilla and oil, and mix at a low speed until fully incorporated. Scrape down the sides of the bowl with a spatula, then beat on medium speed for about 30 seconds.

Divide batter evenly between the prepared cake pans (I find a kitchen scale helpful for this part). This guarantees your layers will bake to be the same height.

Bake for 35-37 minutes (or until a toothpick comes out clean). Allow cake layers to cool for 10-15 minutes on a wire cooling rack before removing from pans – it helps to run an offset spatula or knife around the perimeter of the pan first. Cool completely before frosting. Set in the fridge or freezer to accelerate the cooling process if desired.

If needed, once cake layers are cooled, level them (I don’t generally trim much from the tops of mine). This can be done with a cake leveler or a large serrated knife and a ruler if needed.

Place a smear of frosting on your cake circle (to keep the cake from sliding while you decorate it) and center your first cake layer in the center of the circle.

Spread the first layer with frosting. Add your next cake layer on top, and repeat the process with your remaining cake layers.

Now you're ready to crumb-coat. If you're unfamiliar with crumb-coating, it's just what it sounds like – spreading a thin layer of frosting over the entire outside of the cake to keep crumbs out of your final layer.

Once your crumb coat has set (this takes about 5-10 minutes in the fridge), add your final layer of frosting and smooth. I didn’t worry about smoothing too much since I wanted to texture the frosting with the offset spatula.

Wipe off a small offset spatula, and press the back of the tip gently into the frosting at the base of the cake. As you spin the turntable, gradually move the spatula up the side of the cake, adding a ridged texture to the frosting as you go.

This motion along the top of the cake edge will probably result in a small ‘lip’ or ‘ridge’ of frosting at the top – this is a good thing. ;) Wipe off the offset spatula again, and use it to pull in that ‘lip,’ keeping the spatula even with the top of the cake. Work your way around the cake until the top edge is smooth. Smooth-ish. Whatever. ;)

Feel free to decorate with flowers or berries at this point – or sprinkles like I did! Annnd you’re done! Cut in and enjoy!