In a medium bowl, whisk together melted butter, brown sugar, honey, sourdough discard, and vanilla extract until well combined.

In a large bowl, stir together the all-purpose flour, whole wheat flour, cinnamon, baking soda, and salt.

Pour the wet ingredients into the dry ingredients. Use a rubber spatula to mix until a dough forms. It will be soft but not sticky.

Shape the dough into a rectangle. Wrap it tightly in plastic wrap and refrigerate for at least 1–2 hours or overnight.

On a lightly floured surface, roll the chilled dough out to about ⅛ inch thick. Cut into 2x5-inch rectangles. Use a paper guide for uniform sizing if desired.

To add the classic look, gently press a 1x5-inch strip down the center of each rectangle to mimic a seam. Then fold that same paper strip in half and use it to divide each rectangle into quadrants. Use a toothpick or skewer to poke small holes in each quadrant.

Transfer crackers to a parchment-lined baking sheet. Bake at 350°F (177°C) for 15–18 minutes, depending on your preferred level of crunch.

Let cool completely on a wire rack. Store in an airtight container at room temperature for up to one week.