A disclaimer: the recipe for this is in baker's percentage format. This means you need both a scale and, potentially, a calculator. On the plus side, you get a delicious bread with a bit of crunch, a lot of crumb, and a great crust. Until you stick it in your backpack not 10 minutes out of the oven and bike to work, that is. I don't recommend it with this loaf as the enclosed space and lack of cooling will soften the crust a ridiculous amount. This is one of the better loaves I have cooked, up there with the standard rustic mini baguettes (on which the dough is based), struan, and the previous walnut bread (which had mashed potatoes and potato water as the alternate flour). So, yes, do go out and make this bread. Wonderful, really.
"Country" Walnut Bread
Use 300g total flour for ~1 loaf
75% bread flour
20% whole wheat flour
5% coarse-ground cornmeal (polenta)
80% water (cold)
8% coarsely chopped walnuts
At least a night before you want to make the bread, combine some of the water and the cornmeal in a bowl and let soak for 30 minutes. Add the rest of the ingredients and stir with a wet wooden spoon for 2-3 minutes until the dough has come together plus a minute more. It should be sticky. Cover and let rest for 10 minutes. Then stretch and fold 4 times with a 10 minute rest between each; be careful, as the polenta and walnut will make bread likely to rip. Refrigerate over night.
Day-of baking, remove the dough from the fridge 2 hours before you plan to put it in the oven. Dust a work surface with flour, coat your hands with flour, and gently remove the dough from the bowl and shape into a loaf. Note that, due to the incredibly high liquid, if you shape this into anything other than baguettes you may want to coax it back into shape after an hour as it will have spread out; I assume a banneton would fix the issue, but I don't have one nor nor care to improvise one. For a boule, bake at 450 for 25 minutes, turning after 10-15 minutes. Once the time is up, shut off the oven but leave the bread in for an extra 5 minutes to crisp the crust further. Let cool for an hour if you want to preserve your beautiful crust.