In a large mixing bowl, combine flours, baking powder, and salt.
In a small saucepan on medium heat, melt ¼ cup butter. Remove from heat, add honey, and stir to combine.
Make a well in center of dry ingredients. Add melted butter mixture and buttermilk to the well. Starting from the center, slowly mix dry ingredients into wet to form a cohesive dough. If very sticky, add more rice flour. If crumbly, add a bit more buttermilk.
Knead dough on a clean surface for about 1 minute. Once ingredients are incorporated, wrap in plastic and press flat. Refrigerate for 1 hour to overnight.
When ready to bake crackers, heat oven to 350°F and melt reserved 1½ tablespoons butter. Have a rolling pin and parchment paper ready. Divide dough into three equal pieces. Flour a dry work surface, and roll one piece of dough until it is 1/16-inch thick. Brush with a third of the melted butter and top with seeds. Add sea salt and black pepper to taste. Top with parchment paper and press seeds, salt, and pepper into dough. Transfer to parchment-lined baking sheet. Repeat with remaining dough.
Bake 15 to 25 minutes, until golden brown and fully crisped. Cool, then break into shards for serving.