Preheat oven to 350 °F. Have two half sheet pans and two half sheets of parchment or silicone baking mats ready.
In a bowl, whisk together 2 ½ oz all purpose flour, 4 oz rolled oats, 3 oz stone ground whole wheat flour,1 teaspoon table saltt and ½ teaspoon baking soda. In a large measuring cup, combine4 oz buttermilk and 8 oz sourdough discard. In the bowl of a stand mixer or a large mixing bowl, cream together 3 oz unsalted butter, ½ oz granulated sugar and ¾ oz honey until light and fluffy.
Alternate adding the dry ingredients and the wet ingredients to butter. Mix just until combined. The dough will be somewhat sticky with a texture similar to biscuit dough.
Turn the dough out onto a generously floured surface. Divide the dough into 2 equal portions. Pat each piece to a rectangle, using enough flour to keep it from sticking to the surface and your hands.
Transfer a piece of the dough to a 1/2 sheet parchment paper and use a rolling pin to roll the dough to 1/8" thick and the size of the paper (see note). Trim the edges to make a neat rectangle.
Sprinkle the chopped oats over the surface and press them into the dough. Prick the dough all over with a fork. Score dough into 16 rectangles, or to your desired cracker size. Repeat with the other portion of dough.
Bake about 15-20 minutes until golden brown and crisp. Cool on a rack for 5 minutes before breaking along scores. It's easier to break the crackers when they're still slightly warm.
Store in a sealed container.