Sourdough Rhubarb Cookies – Sourdough Brandon

These Sourdough Rhubarb Cookies combine sweet-tart pockets of fresh rhubarb with creamy white chocolate and rich, nutty brown butter for a bakery-style cookie that’s crisp around the edges and soft and chewy in the center.

The tangy rhubarb balances the sweetness of the white chocolate, while brown butter adds a deep caramelized flavor that makes every bite taste a little more special. Sourdough discard gives the cookies subtle complexity and helps create an irresistibly tender texture.

If you’re looking for a unique spring or early summer cookie, these are sure to become a new favorite sourdough cookie.

Follow my detailed instructions with photos and tips below to make the best sourdough rhubarb cookies every time.

👍 Why You’ll Love This Recipe

🔍 Expert Baking Tips

• Use chopped chocolate for the best results. You’ll get puddles of large chocolate and smaller bits throughout in every bite.
• I tested the recipe at various temperatures and 325ºF allowed just the right amount of spread and chewiness.
• You can macerate the rhubarb ahead of time to reduce some of the juiciness, but I didn’t find much of a difference in recipe testing.
• Let the brown butter cool to room temperature before mixing in wet ingredients.
• Weigh your cookie dough balls so you get equal-sized cookies like I do for Sourdough Discard Chocolate Chip Cookies, Sourdough Sugar Cookies, and Sourdough Ginger Molasses Cookies.
• For perfectly circular cookies, swirl hot cookies in a cookie cutter to round the edges.
• Rest the cookie dough for at least 30 minutes for better flavor and easier shaping.

• Baking scale
  • Flour and sourdough starter can vary in weight from person to person, so weighing your ingredients is the best option! Measuring your ingredients by weight will make your baking more consistent and accurate.
• Sheet Pan, lined with parchment paper
• Spatula and Whisk, for mixing the cookie ingredients

🛒 Ingredients Needed

See below for my ingredient recommendations and possible substitutions.

• All-purpose Flour
  • You can substitute some of the all-purpose flour with whole wheat flour for more nutrition and wheat flavor.
• Salt
• Baking Soda creates a chewy texture and helps the cookies spread.
• Unsalted Butter
• Vanilla Extract enhances flavor and adds warmth and the perception of sweetness.
• Granulated sugar
  • Adds structure and sweetness to the cookies.
• Eggs
  • Adds structure to help bind the ingredients together.
  • To make egg-free, substitute with an egg replacer or flax egg.
• Sourdough Discard
• White Chocolate

Variations

• Add ½ cup of toasted walnuts, macadamia, or pecans for crunch.
• Add 1 teaspoon of cinnamon, cardamom, ginger, or a mix of spices.
• For more brightness, zest an orange into the dough.

🍪 How to Make Sourdough Rhubarb Cookies

Follow this detailed recipe guide with step-by-step images as you make the best rhubarb cookies.

1. Brown Butter

Melt the butter in a light-colored saucepan over medium heat so you can easily monitor the color. As it heats, the butter will foam and sizzle while the water cooks off, and the milk solids will begin to toast at the bottom of the pan.

Stir or swirl occasionally to keep everything cooking evenly. After a few minutes, the butter will turn a deep golden color and develop a rich, nutty aroma. Remove from the heat and pour it into a heatproof bowl right away to stop the cooking and prevent it from burning.

Let it cool to room temperature before using.

2. Mix the Dry Ingredients

As the butter cools, whisk the all-purpose flour, salt, and baking soda together in a small bowl and set aside.

3. Mix the Wet Ingredients

In a large mixing bowl, whisk the cooled brown butter, sugar, eggs, vanilla, and sourdough discard.

4. Mix the Cookie Dough and Rest

Add the dry ingredients to the bowl and mix until mostly incorporated.

Then, fold in the chopped rhubarb and white chocolate chunks with a spatula.

Cover and refrigerate the cookie dough for at least 30 minutes to infuse the flavors and make shaping easier.

5. Bake

Preheat the oven to 325ºF (163ºC) and line baking sheets with parchment paper to prevent sticking.

Scoop out 2 ½ TBS of cookie dough, or about 50g each. Roll into balls and place a few inches apart on the prepared pans.

For large pools of chocolate, chop large chunks of white chocolate and rhubarb and stick on top. Sprinkle with optional, crunchy raw sugar.

Bake for 14-15 minutes or until the cookies are just set around the edges. Give the pan a light tap on the counter a couple of minutes before they’re done baking and after they’re baked to help flatten them.

Cool for at least 15 minutes on a wire rack.

How to Store and Serve

• Store in an airtight container at room temperature for up to 2–3 days. These cookies soften quickly because of the fresh rhubarb.
• If stacking, keep the cookies separated with parchment paper so they don’t stick to each other.
• For longer storage, freeze baked cookies for up to 2 months.
• Freeze cookie dough balls and bake fresh as needed. They may need a couple of more minutes in the oven.
• Let cookies cool completely before storing to keep edges crisp.
• Warm slightly before serving for gooey chocolate and the best texture.

❓ Frequently Asked Questions