I did a few things differently with this loaf: I improvised a proofing couch, consisting of some wine bottles and a rolling pin. I placed each loaf sandwiched (with a little room to spread) between two of these firm surfaces. They didn't lose any of their shape as they rose/proofed, but I can't say it was all due to the couch. This dough was very firm and probably would have held just fine. To avoid the splitting at the seams, instead of using an equal amount of dough for each layer, I would use more for the outer layers so as to not stretch it so thin on the outermost wrap. At least one of the loaves didn't burst, but I haven't cut into it yet so I don't know what the inside did.
Soft Rye Sandwich Bread
Makes 1 small loaf (pictured is 2 of these recipes)
~15 minutes at night, 3+ hours the next day (2.5ish hour rise, 35 minute bake, cool)
227g bread flour
71g light rye flour
145g lukewarm water
19g vegetable oil
2g + a little more instant yeast
10g cocoa powder (optional, to get a dark loaf)
60g heavy whipping cream (or buttermilk, or yogurt)
10 or so fennel seeds
To make it as I've (attempted) to, make two of these recipes - one with cocoa powder and one without.
Combine all the dry ingredients and mix together. Add in liquids and stir vigorously for 2-3 minutes. It should get a little tough to stir due to the rye flour. Let rest for 5 minutes, then stir again for 2-3 minutes. The dough should form a ball and be tacky; if not, adjust by adding more water (if it is too dry) or bread flour (if it is sticky). Transfer to a lightly-floured work surface and knead for 30 seconds or so, adjusting by feel. Form back into a ball and place in a fridge for at least one night.
Remove the dough from the fridge. Rip the dark and light balls into four pieces, each. Roll the pieces out into a rectangle about as long as you want the loaf, and 5-ish inches wide. For the center piece, letter fold it, sealing the seam, and rock back and forth to get it rounded. Take the next piece, of the opposite color, and wrap it around (sealing the seam tightly). Do two more layers and then place on a parchment-lined pan. Lightly spray the dough with oil and cover with plastic.
Let it rise for 2-3 hours, until it has grown to 1.5 times its original size. Preheat the oven to 400 degrees; when heated, place the bread in the oven for 15-20 minutes, rotate the loves, and let them cook for 20-30 more minutes. Look for the telltale "done" signs: the crust looks a little browned, they sound hollow when thumped. If you have a thermometer, 190 degrees is the temperature you want in the center. Let cool for around an hour before slicing.