Sourdough Thumbprint Cookies [with jam]

These simple homemade sourdough thumbprint cookies are a great way to use up your sourdough discard or extra sourdough starter. You can ferment them a little before you bake them to get the health benefits or bake them right away - the choice is yours!

As a must-have holiday cookie, they make a delightful Christmas gift.

But they are also an easy way to fill up the cookie jar - you might even like to bake them with the kids! It's a great recipe to get them involved in all things sourdough!

If you are a cookie monster, you might also like these sourdough cookie recipes - sourdough chocolate chip cookies, sourdough snickerdoodles, sourdough gingerbread cookies or cut out and decorate sourdough sugar cookies.

What Are Thumbprint Cookies?

Thumbprint cookies are a cake-like cookie that have a small indent in the centre - this is the "thumbprint", however it's much easier to make the indentation with a small teaspoon.

Depending on where you live, they might also be called "jam drops". In Australia, they are a very popular biscuit and a great way to use up much loved homemade strawberry jam.

In Sweden they are called "Hallongrotta" which translates to "raspberry caves".

They are popular during the holiday season because they are easy cookies to bake.

Can I Ferment Sourdough Thumbprint Cookies?

You can leave the cookies in the fridge for up to 24 hours before baking. I recommend shaping the cookies and leaving in the fridge on the baking tray as the dough gets very hard in the fridge and will difficult to shape.

You can bake the cookies straight from the fridge. I don't cover them with plastic wrap if leaving them in the fridge as they tend to form condensation.

You can ferment the cookies whether you use sourdough discard or active sourdough starter. It doesn't really matter which you use, just make sure that you're using a sourdough starter that is 100% hydration, that is it has been fed with equal amounts of flour and water by weight.

Sometimes when making sourdough bread, I'll feed my sourdough starter a bit extra so that I have enough to make these cookies.

How To Make Sourdough Thumbprint Cookies

These are really easy cookies to prepare and bake. I find it easier to use an electric hand mixer (electric mixer) to cream the butter and sugar together, however you could also use a stand mixer to do this.

1. Prepare 2 cookie sheets with parchment paper.
   
2. If you are going to bake the cookies straight after forming them, preheat the oven to 350F (180C). If you are going to ferment them, do not preheat the oven.
   
3. Cream the softened butter and sugar using a hand mixer or stand mixer with a paddle attachment. The mixture should be light and fluffy.
   
4. Now add the egg and egg yolk, vanilla extract and sourdough starter to the butter and sugar mixture and mix on moderate speed until well combined.
   
5. Next add the all purpose flour, baking powder and pinch of salt to the wet ingredients and bring together into a dough (you can use a wooden spoon or your hands if you prefer - I find this step easier to do by hand as the stiff dough will bog the hand mixer).
   
6. Use a spoon or cookie scoop to scoop out balls of dough. Roll the dough balls a little and place them onto the prepared baking trays. I find the balls are perfect around 15g each, but you can go up to 20g.
   
7. Use a small spoon (half teaspoon is perfect) to make a small indent in the centre of each cookie. This is the "thumbprint" but a spoon is much easier.
   
8. ** if you want to ferment the cookies, place the cookies into the fridge at this point. You can leave them up to 24 hours in the fridge)** (see notes for further information).
   
9. Use a small spoon to place a little jam into the center of each cookie. You don't want to overfill them or they will make a mess in the oven.
   
10. Place the sourdough thumbprint cookies into an oven at 350F (180C) for around 15 to 18 minutes or until they are just golden and the jam is bubbling. It's better if they are placed on the top rack of the oven.
    
11. Remove from the oven and allow to sit for 5 minutes on the cookie sheet before transferring to a cooling rack to firm up.

Ingredient Notes & Flavor Variations

• If you are using salted butter, leave out the pinch of salt. Butter must be soft, NOT melted, or it won't cream properly with the sugar. Butter kept at room temperature is best for making these cookies.
  
• If you'd prefer not to use white sugar, you can use brown sugar or even coconut sugar but it will change the color and texture of the sourdough thumbprint cookies.
  
• I love making these sourdough thumbprint cookies with strawberry jam but I've also made them using apricot, blueberry, raspberry and whatever other jam flavors we have on hand at the time. Use whatever you have and your family will love.

• If you'd prefer a neater jam filling, you can add the jam to a piping bag, but I like to keep things super simple!
  
• You can add other things to the cookie dough to give it extra flavor if you'd like - crushed macadamia nuts or chopped pecans, warm spices like cinnamon or ginger, lemon or orange zest are all lovely additions to these simple cookies.

How to Store + Freeze

These cookies will last around a week in an airtight container. It's better to store them in glass than plastic as they will go soft much quicker in a plastic container.

You can freeze unbaked cookies and bake them when you need freshly baked cookies. Add the jam in the centre before you freeze them. Store frozen, unbaked cookies in a zip loc bag.