Muscle Momma Sourdough

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I have some pretty picky eaters in my house- even when it comes to sweets. So when I tested these sourdough discard birthday cake cookies, I honestly wasn’t sure how they’d go over. But when my husband took one bite and said, “You have to put these on your website, these are amazing,” I knew they were a winner.

These cookies are soft, chewy, and full of birthday cake flavor, thanks to the combo of white chocolate chips, rainbow sprinkles, and a touch of almond extract. They’re made with sourdough discard, giving them a subtle tang that balances the cake flavor.

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Sourdough Discard Birthday Cake Cookies Recipe:

Ingredients:

Unsalted butter (½ cup / 113g): Butter is the base of this recipe, giving the cookies richness and a tender crumb. I use unsalted so I can control the salt level myself.

Granulated sugar (¾ cup / 150g) + Brown sugar (¼ cup / 50g): The blend of sugars gives the cookies just the right balance—granulated sugar brings structure and sweetness, while brown sugar adds moisture and that soft chew we all love.

Sourdough discard (¼ cup / 60g): The star of the show! It adds a subtle tang and perfectly balances the birthday cake flavor. Plus, it’s a great way to reduce food waste!

Egg (1 large): Eggs provide structure and moisture. Without it, the dough would be too crumbly and dry.

Vanilla extract (1 tsp) + Almond extract (½ tsp): These two together are what give the cookies that nostalgic “birthday cake” flavor. Almond extract especially is key!

All-purpose flour (1¾ cups / 220g): Just the right amount to give structure without drying the cookies out. Depending on the hydration of your discard, you might need to add a little extra flour (see tips in recipe below).

Baking powder (¾ tsp) + Baking soda (½ tsp): A combo of both helps the cookies rise while staying soft in the center.

Salt (½ tsp): Enhances the flavors and balances out the sweetness.

White chocolate chips (½ cup / 90g): These melt into little pockets of creamy sweetness and pair perfectly with the cake batter flavor.

Rainbow sprinkles (¼ cup / 40g): Because birthday cake cookies should look like a party too! I prefer jimmies (the longer, softer kind) because they don’t bleed color into the dough.

Instructions:

1. Cream the butter and sugars: In a large mixing bowl, beat ½ cup softened butter, ¾ cup granulated sugar, and ¼ cup brown sugar until light and fluffy (about 2–3 minutes).
2. Add the wet ingredients: Mix in ¼ cup sourdough discard, 1 large egg, 1 tsp vanilla extract, and ½ tsp almond extract until fully combined.
3. Whisk the dry ingredients: In a separate bowl, whisk together 1 ¾ cups all-purpose flour, ¾ tsp baking powder, ½ tsp baking soda, and ½ tsp salt.
4. Combine wet and dry: Gradually mix the dry ingredients into the wet until just combined. If the dough feels too wet or sticky, add a bit more flour, 1 tablespoon at a time. This can happen if your discard is on the wetter side.
5. Fold in the fun: Gently fold in ½ cup white chocolate chips and ¼ cup rainbow sprinkles until evenly distributed.
6. Scoop and chill: Scoop the dough into 14-16 evenly sized balls. Place them on the baking sheet and chill in the fridge for 30 minutes to 1 hour for thicker cookies.
7. Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.
8. Bake: Place chilled dough balls on a lined baking sheet and bake for 10–12 minutes, or until edges are set and centers are slightly under baked.
9. Cool and enjoy: Add extra sprinkles and white chocolate chips on top of the cookies fresh out of the oven. Then, let cool on the baking sheet for 5 minutes before transferring to a wire rack.

Tips for the Best Cookies

• Use both vanilla and almond extract: This combo gives it that nostalgic birthday cake flavor.
• Chill for thicker cookies: Chilling the dough for 30 minutes to 1 hour helps them stay thick and chewy.
• Don’t overbake: Take them out when the centers still look a little underdone. They’ll finish setting as they cool.

If You Liked This Recipe, Try These Next:

• Sourdough Discard Single-Serve Cookie Skillet – A gooey, golden cookie skillet that uses sourdough discard and comes together in minutes. Perfect for one (or two, if you’re feeling generous).
• Sourdough Discard Protein Bagels -A high-protein twist on classic bagels—made with sourdough discard and Greek yogurt for added nutrition. Great for meal prep and easy to customize with your favorite toppings.
• Sourdough Discard Pumpkin Muffins – Moist, warmly spiced, and naturally sweetened with maple syrup. These muffins are a cozy and wholesome way to use up extra discard.