https://www.myrecipes.com/how-to/creative-ways-to-use-buttermilk
Waste Not What You Bought: 16 Ways to Use Leftover Buttermilk
1. Biscuits
After baking hundreds of biscuits, our test kitchen landed on this winning recipe for Our Favorite Buttermilk Biscuit. This so-simple, no-fail formula for the most tender buttery biscuits will impress new cooks and old pros alike.
2. Coffee Cake
If you're ready to step up your brunch game, this beautiful cake will definitely do the trick. Serve with lots (and lots) of coffee.
3. Mashed Potatoes
Buttermilk adds a rich creamy factor and tangy depth to these garlicky mashed spuds. They're really easy to make, so there's no reason you can't put them your dinner menu tonight.
4. Brownies
A good brownie recipe becomes great with these 6 customized variations: Coconut-Macadamia, Peanut Butter and Pretzels, Coffee Bean, Malted Toffee, Oreo Cheesecake Swirl, and Honey-Nut. Click the image above to get the recipe for each of these delightful additions.
5. Icebox Pie
Sweetened condensed milk and buttermilk are the dream cream team that makes this gingersnap crusted icebox pie insanely rich and irresistible.
6. Soup
That's right, buttermilk can definitely go beyond the baking to drastically improve your soup game as well. The brightness it provides is perfect for paring with summer flavors, like in the Lady Pea Soup pictured above.
7. Fried Chicken
There's no way I was about to do a buttermilk recipe round-up and NOT mention fried chicken. These delicious homemade chicken fingers are great for an effortless and kid-friendly weeknight meal.
8. Homemade Hamburger Buns
Hello, weekend baking project. Significantly fresher and more flavorful than store-bought, these big, pillowy buns are well worth the effort. Plus, it's pretty legit to say you know how to make your own burger buns, like a boss. This recipe might make more than what you need for a single meal, but the buns freeze well.
9. Muffins
Here's a breakfast muffin you don't have to feel bad about. We opted for canola oil over butter, incorporated 50% white whole-wheat flour, and kept the added sugar low by leaning on the sweetness of ripe summer strawberries, blueberries, and raspberries. Boom.
10. Homemade Ranch Dressing
Not only is ranch easy to make at home, it's way tastier and healthier than any bottled stuff you'll find at the store. Trust me, once you go DIY on this one... you will never look back.
11. Cornbread
This tender, cast-iron skillet cornbread is guaranteed to become a go-to recipe. Plus, it uses up 2 1/2 cups of that carton of buttermilk in your fridge. That might just be enough to empty it (but then you'll go buy more so you can make this recipe again--just a heads up).
12. Smoothies
This quick smoothie comes together in a flash. Just dump all ingredients in a blender, puree until smooth, and breakfast is served. Buttermilk adds a delightful tanginess to balance the sweet fruit.
13. Pound Cake
Unsweetened cocoa, cacao bittersweet chocolate morsels, and semisweet chocolate morsels combine to form a most powerful choco-squad in this indulgent triple-chocolate pound cake.
14. Pancakes
I'm telling you people, I love me some buttermilk pancakes. Now, don’t be fooled by their rich flavor, these light and fluffy pancakes deliver half the fat and all the scrumptious comfort food personality of your typical short stack.
15. Ice Cream
Dress up scoops of tangy buttermilk ice cream with in-season berries, sliced stone fruit, or lemon rind strips. P.S. waffle bowls are always the right thing to do.
16. Cream Cheese Spread
This simple spread is an amazing choice for any toast or crostini. The velvety smooth texture of the buttermilk-cream cheese mixture complements fresh vibrant produce and makes a marvelous bed for cured meats. While simple and satisfying, this creamy spread allows the flavors of any other desired toppings to shine through.