Sourdough Peanut Butter Spider Cookies

These Sourdough Peanut Butter Spider Cookies are a playful Halloween twist on my beloved Amish Peanut Butter Cookies-the soft, chewy classic that everyone loves.

This recipe uses an  Amish Friendship Sourdough Starter for a little extra depth of flavor and that perfectly tender texture, but don’t worry, regular sourdough discard works beautifully too. Topped with mini peanut butter cups and chocolate “legs,” they’re as cute as they are delicious, making them the perfect spooky-sweet treat for fall gatherings, parties, or a fun weekend bake!

What is an Amish Friendship Starter?

An Amish Friendship Bread starter is a fermented mixture that acts as the base for the bread, similar to a sourdough starter. It’s traditionally made with flour, sugar, and milk, which is left to ferment at room temperature over a few days. This fermentation process gives the bread its signature light, airy texture and mild sweetness.

The starter is often shared among friends, allowing others to continue the baking tradition. Some variations may also include yeast to help kickstart the fermentation process.

All of my Amish recipes are inspired by the classic friendship starter—this is my personal take on it however it is not the exact same method.

If you want to learn more about my variation on a classic check out this article!

Why use an Amish friendship sourdough starter in cookies?

Honestly, I’ve never been the biggest fan of sourdough discard cookies-the water-based starter tends to make them a little bready, and you have to fuss with things like browning the butter just to balance it out. But the Amish friendship starter is different. Because it’s milk-based and lightly sweet, it gives cookies that soft, classic texture and flavor I’ve been looking for, without the extra steps. It’s the one starter that actually makes me love sourdough cookies.

Just take a look at that texture!

Why I love this recipe

• Incredibly Light & Fluffy Texture – Thanks to the Amish Friendship Sourdough Starter, these cookies have an airy, almost cloud-like softness that makes them irresistibly tender.

• Depth of Flavor – The subtle tang from the starter enhances the rich peanut butter taste, creating a more complex, well-balanced sweetness.

• Easy & Foolproof – No complicated steps—just mix, scoop, and bake! The starter does the magic, making this recipe perfect for both beginners and experienced bakers.

• Perfectly Sweetened – These cookies strike the perfect balance between sweet and nutty, making them an ideal treat without being overpowering.

Tools for success

A few simple tools make decorating these spider cookies so much easier (and way more fun!):

• Squeeze Bottle – My go-to for piping the chocolate “legs.” It gives you perfect control and clean lines without the mess of a piping bag.

• Candy Eyes – These are the perfect size for the mini peanut butter cup “spiders.” Not too big, not too small — just right for that cute (not creepy!) Halloween look.

• Food scale – Helps weigh the ingredients, but also the cookies themselves for the perfect size every time!

How to make sourdough peanut butter spider cookies: step-by-step

Baker’s schedule: Make the Amish friendship starter (milk starter) the evening before you make the cookies. If using discard this step can be skipped. Use a discard that is no more than a week old to avoid a sour taste.

Yields 24 large cookies. though the final count may vary depending on how big you make each cookie.

Using regular sourdough discard? No problem! Keep the recipe the same, but increase the flour to 270 grams & substitute 100 grams (1/2 cup) of the brown sugar with white sugar to balance the extra moisture.

Peanut Butter: A natural peanut butter can be used but because it has a more liquid-like consistency, some additional flour will need to be added to the dough.

Ingredients

For the Amish friendship sourdough starter:

• 20 grams of active sourdough starter
• 20 grams of sugar
• 100 grams of milk
• 100 grams of all-purpose flour

For the peanut butter cookies cookies:

Wet Ingredients:

• 200 grams (1 cup) Amish friendship sourdough starter or regular sourdough starter
• 180 grams (3/4 cup) creamy or chunky peanut butter
• 113 grams (1/2 cup) unsalted butter, room temperature
• 200 grams (1 cup) light brown sugar
• 1 large egg (room temperature)
• 5 grams (1 teaspoon) vanilla extract

Dry Ingredients:

• 250 grams (2 cups) all-purpose flour
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1/2 teaspoon salt
• 100 grams granulated sugar (for rolling)
• 1/2 cup melted chocolate for the spider legs (I use dark chocolate)
• Candy eyes and 24 peanut butter cups
• coarse sugar for topping (optional)

Equipment

• Large baking sheet
• Parchment paper
• Food scale/ measuring cups and spoons
• Stand mixer or hand mixer
• Squeeze Bottle or piping bag for the spider legs

Instructions

Make the Amish friendship starter:

• The evening before you make the cookies, mix the Amish starter ingredients (sourdough starter, milk, sugar, & flour) in a glass jar. It will be thicker in texture. Cover it loosely and allow it to rest overnight for 8-10 hours. It will double in size by the morning and be light and fluffy in texture.

The following morning

*If using regular sourdough discard see notes above for adjustments on ingredients *

• Begin by creaming the softened butter and sugar in a large mixing bowl. Beat together until light and fluffy.

• Next, mix in the peanut butter and egg until fully Incorporated. Then stir in the Amish friendship sourdough starter (or regular sourdough discard) and vanilla extract until combined.

• In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.

• Gradually mix the dry ingredients into the wet ingredients until fully combined. If the dough seems too sticky add a little more flour.

• Cover the dough and place it into the fridge for 30-60 minutes. Sourdough peanut butter cookie dough can be refrigerated for up to 24 hours.

How to bake & assemble sourdough peanut butter spider cookies

Tip: place the peanut butter cups in the freezer to avoid from melting later.

• When ready to shape and bake the peanut butter cookies line a large baking sheet with parchment paper and preheat the oven to 350 degrees F.

• Portion and weigh the dough so each cookie is 40 grams. Roll each into a ball and then roll in the granulated sugar and place on the lined baking sheet. Ensure each cookie is spaced 1 to 2 inches apart on the baking sheet for even baking.

• Bake the cookies for 15 minutes If making smaller cookies, adjust the time accordingly (they may only need 8-10 minutes).

• Remove the cookies from the oven and firmly tap the tray on the counter to create those signature bakery-style cracks. This step is optional, but it adds a beautiful finish to the cookies.

• Place the cookies back in the oven for 2-4 more minutes to ensure they are done baking. Every oven is different, so yours might only need the initial 15 minutes.

• Let the cookies rest on the baking sheet for 5 minutes before assembling them.

• Once the cookies have cooled just slightly (still a bit warm to the touch), press a peanut butter cup upside down into the center of each cookie. Gently press so it sticks but doesn’t sink too deep.

• Transfer the cookies to the freezer for 5–10 minutes to help the chocolate firm up and prevent melting while decorating.

*If your peanut butter cup starts to melt, just let the cookies cool completely and use a little melted chocolate to “glue” it back on- it works perfectly!

• Fill a squeeze bottle or piping bag with melted chocolate and pipe 8 legs total, four on each side of the peanut butter cup. Short, slightly curved lines look most natural.

• Use a tiny dab of melted chocolate as “glue” to attach two candy eyes to the front of each peanut butter cup, as if the spider is peeking out from the cookie.

• Allow the chocolate to set completely before serving or storing- you can pop them in the fridge for a few minutes to speed it up and enjoy!

How to store sourdough peanut butter spider cookies

• Store the cookies in an airtight container at room temperature for up to 5 days. If your kitchen is warm or humid, keep them in the refrigerator to prevent the chocolate decorations from softening.

• For longer storage, you can freeze the cookies (without the candy eyes) for up to 2 months, just thaw at room temperature before serving.

More sourdough dessert recipes

• Sourdough Peanut Butter Cup Cookies
• Ghost Sourdough Jammie Dodgers
• Easy Sourdough Donuts
• Amish Friendship Chocolate Chip Cookies (sourdough option included)