1) Preheat the oven to 400°F. Lightly grease a baking sheet, or line it with parchment.
2) In a medium-sized mixing bowl, whisk together the flours, Harvest Grains Blend, baking soda, and salt.
3) In a separate bowl (or in a measuring cup), whisk together the starter, butter, honey, and milk. Pour this mixture into the dry ingredients and stir to combine. The dough will be stiff; if it's too crumbly to squeeze together, add another tablespoon or two of milk.
4) Knead the dough a couple of times to make sure it's holding together, divide it in half, and shape each half into a ball. Flatten the balls slightly, and place them on the prepared baking sheet. Use a sharp knife to cut a ½"-deep cross, extending all the way to the edges, atop each loaf.
5) Bake the loaves for 30 to 40 minutes, until they're golden brown and a cake tester or toothpick inserted into the center comes out clean. Remove the loaves from the oven, and brush their tops with melted butter, if desired.
Yield: two 6" to 8" loaves.