By Luna turned two last week, in February. The second birthday, which is the birthday where you can see the personality beginning to crystallize. Kai at two had been intense and physical and constantly in motion. Luna at two is focused and precise and moves with purpose. She has decided she wants to help cook and by "help cook" I mean stand on the step stool I made for Kai and supervise everything I do at the counter with the critical attention of a sous chef who does not entirely trust the head chef's judgment.
I made her a birthday cake — not from a box, from scratch, Hannah's grandmother's yellow cake recipe that has been in the family since before anyone wrote it down formally. Cream butter and sugar until pale. Beat in eggs one at a time. Alternate flour and buttermilk. Bake at 350 for thirty minutes. Frost with chocolate buttercream. Luna inspected the frosting process with great interest and then put one finger in the bowl when I turned my back, which I saw in my peripheral vision and chose to allow because it is a birthday and you get one fingerful of frosting on your birthday.
She ate her birthday cake by eating the frosting off the top first, systematically, section by section, with a spoon. Then she ate the cake underneath, still with the spoon. This is not how you eat birthday cake, except that she is two and she has decided that organized disassembly is the correct approach to this specific problem, and at two you get to have the approach that makes sense to you. She is going to be an engineer. Or a surgeon. Or a cook who approaches every dish as a problem to be solved in the most efficient sequence. That last one would be fine with me.
Danny called on her birthday. He sang to her on the phone, which is something he has never done before — it was a few notes of something, possibly Happy Birthday in Cherokee, possibly a Cherokee song I did not know, and then he stopped and said: "Wado" into the phone. Luna, who was standing next to me, said: "Wado, Grandpa Danny." Two years old and already having phone conversations. She is ahead of schedule on everything.
That line in Hannah’s grandmother’s recipe — “alternate flour and buttermilk” — is the one that trips people up most, because buttermilk isn’t always in the refrigerator when inspiration strikes or a small person turns two and needs a cake. I’ve made this cake enough times to know that getting the buttermilk right, or right enough, is the difference between a cake Luna would eat systematically with a spoon and one that just sits there. If you want to bake this kind of cake — the real kind, the kind worth supervising — here’s what you need to know about buttermilk and what to do when you don’t have it.
Buttermilk Substitutions
Prep Time: 5 minutes | Cook Time: 0 minutes | Total Time: 5–10 minutes | Servings: Makes equivalent of 1 cup buttermilk per method shown
Ingredients
- Method 1 — Milk + Acid (most common): 1 cup whole or 2% milk + 1 tablespoon white vinegar or fresh lemon juice
- Method 2 — Yogurt: 3/4 cup plain whole-milk yogurt + 1/4 cup whole milk, whisked together
- Method 3 — Sour Cream: 3/4 cup full-fat sour cream + 1/4 cup whole milk, whisked together
- Method 4 — Kefir: 1 cup plain whole-milk kefir, used as-is (1:1 substitution)
- Method 5 — Cream of Tartar: 1 cup whole milk + 1 3/4 teaspoons cream of tartar, whisked until dissolved
Instructions
- Choose your method. Select a substitution based on what you have on hand. Method 1 is the most reliable all-purpose option for cakes, muffins, and quick breads. Methods 2 and 3 add a bit more richness and are excellent in yellow or buttermilk layer cakes. Method 4 is the closest in flavor and acidity to true cultured buttermilk. Method 5 works well when you need a very neutral flavor.
- Combine and rest (Method 1 only). Add the vinegar or lemon juice to a liquid measuring cup, then fill to the 1-cup line with milk. Stir briefly and let sit for 5 minutes. The milk will curdle slightly and thicken — that’s exactly what you want. It won’t look pretty, but it will work.
- Whisk smooth (Methods 2, 3, and 5). Combine the ingredients in a small bowl or measuring cup and whisk until fully incorporated and no lumps remain. Use immediately.
- Measure carefully. Always substitute in a 1:1 ratio by volume. If your recipe calls for 1/2 cup buttermilk, make or measure 1/2 cup of your chosen substitute using the same proportions scaled down.
- Use in place of buttermilk. Substitute directly into your recipe at the point where buttermilk is called for. For layer cakes, alternate adding your dry ingredients and your buttermilk substitute in thirds, beginning and ending with the dry ingredients, just as you would with real buttermilk.
- Note on non-dairy substitutions. For a dairy-free version, substitute unsweetened oat milk or full-fat coconut milk with 1 tablespoon of white vinegar or lemon juice per cup. Let sit 5 minutes before using. The texture and rise will be slightly different but will still produce a tender crumb.
Nutrition (per serving)
Calories: 35 | Protein: 2g | Fat: 1g | Carbs: 4g | Fiber: 0g | Sodium: 45mg
Nutrition estimated for Method 1 (1/4 cup serving of whole milk + vinegar substitute). Values will vary by method and milk fat content.