75g firm starter
25g ww or rye flour
275g high-gluten flour (if using bread flour or AP, adjust the water)
1/2 ounce dried onions (soaked in hot water for a couple of hours, then drained; use the water drained from the onions as part of the water in the dough)
3 tbsp poppy seeds
Mix starter and water, add the rest and mix, wait 20 minutes, *fold in the bowl, wait 10 minutes (3 or 4 times from *), cover and refrigerate overnight. Remove from fridge, flatten on lightly oiled counter, *envelope fold, cover with bowl, wait until dough relaxes, maybe 15 minutes (3 or 4 times from *), let rise until when snipped with scissors you see a holey network (thanks, Dan Lepard, for that hint). BTW, the last two times the dough is folded, round it up well. Turn the dough ball to create surface tension, let rest for 5 minutes to seal the bottom, then overturn into a banneton. Let rise for ~3 hours at room temp. Turn out onto parchment, slash, spray with water, load into 500F oven, cover, bake for 20 minutes, remove cover, lower heat to 460F and bake for 10 minutes. Turn off oven and leave for 5 minutes.
If you'll notice, this recipe is basically the same as the Faux Deli Rye, I just twisted things a bit here and there.