Add the whole wheat flour, cinnamon, baking soda, and salt to a large bowl. Whisk well to combine, then set aside.

In the bowl of a stand mixer (or a separate large bowl with an electric mixer), add 7 tablespoons of softened butter and 1 cup of packed brown sugar.

Cream the butter and sugar together using the paddle attachment for 2-3 minutes, or until the color has lightened and it’s fluffy in texture. Be sure to stop the mixer and scrape down the sides of the bowl as needed.

Add the sourdough starter, honey, and vanilla extract to the creamed butter and sugar. Mix just until combined.

Add half of the dry ingredients, and mix just until the flour is absorbed.

Pour in the remaining dry ingredients, and mix gently again - just until nearly combined.

Wet your hands and shake off the excess, then try to bring the dough into a cohesive ball. If it does not do so easily (too sticky), add a little more whole wheat flour and knead it gently by hand. The dough should be sticky, but still able to come together into a soft form. (On the other hand, If the dough is crumbly, try adding 1 tablespoon of milk, kneading, and continuing until a soft, slightly sticky dough forms).

Once the dough comes together, and is slightly sticky, you’re ready to divide the dough into 2 portions.

If possible, weigh the dough on a tared scale and divide the total by half. This is the weight that each divided dough portion should be. (Each half should be about 400 grams, but it may vary depending on the time of year).

Flatten each dough portion into a rectangle, and wrap it tightly in two layers of plastic wrap.

Chill for at least 3 hours, or for up to 3 days. For the benefits of long fermentation 24-48 hours is my recommendation, but 3 day cookies taste amazing too!

Use a rolling pin to roll the dough into a large, flat rectangle, about the size of the inside of a baking sheet, leaving about 1” of margin. As you roll, press any cracking edges together with your hands to prevent further cracks.

Divide the rolled dough in thirds along the bottom, making lines every 4-5 inches. Then, divide the dough in half along the long side, making a line about 7 inches from the edge. You should have 6 rectangles that look like a large graham cracker sheet. Each one should be 4x7” roughly, or up to 5x7”, depending on how thin you rolled your dough.

Use a thin spatula to gently release each rectangle from the parchment paper, and shift it away so each of the graham cracker sheets are at least 1-2 inches apart.

Transfer the parchment paper to a baking sheet.

Use the tines of a fork (or a toothpick) to prick the dough in each quadrant, in the style of a classic graham cracker.

Bake in the preheated oven for 10-13 minutes, or until the edges begin to brown. (We like ours crispy, so 13 minutes is the sweet spot for us).

If you plan on using these to make yummy sourdough s’mores, separate each sheet in half by using a butter knife to cut along the horizontal score line. Quickly separate them while hot, and as they cool they will crisp up nicely.

Repeat all previous steps with the remaining half of the dough.

Allow graham crackers to cool completely before transferring them to an airtight storage container.