Not long ago, I promised to try to curb this tendency to apologize, and I will, but not this morning. Dear friends, I am sorry for the paucity of text of late. I never thought I would become one of those bloggers who saved all her best—nay, only—writing mojo for the weekend, but the combined stresses of LuthorCorp and an uncertain future have left me swimming in a tedious cocktail of laziness and distraction. Case in point: This time last year, I was preparing for four hours of pudding-steaming for the What’s for Pud? roundup compiled by Sam at Becks & Posh and Monkey Gland at Jam-Faced. This year finds me staring at the calendar in a panic, realizing that contributions to this year’s roundup, Fish & Quips, are due on April 20, which is next Friday, realizing that I have no idea what to make, heading to the cookbook stack, quickly becoming overwhelmed by the embarrassment of riches contained within it, and retreating to the bath, wondering if Sam will make me turn in my English Food is a Very Good Thing club membership card. (Fear not, Sam: I may be down, but I’m not out just yet.)
Even as I am thus affected, I have not forgotten that there are things I have been wanting to share with my friends, not least the long-promised, long apologized-over, long-written russenzopf recipe, as well as the overdocumented photo series of the process over at Flickr. With the permission of the good folks at King Arthur Flour, and with the assistance of the lovely and tenacious Gina of Lindsey’s Luscious who did the weight-to-volume-conversion dirty work, I hereby present the recipe for one of the best pastries you could ever eat, an entire batch of Danish pastry in two loaf pans, leavened with yeast, enriched with butter (and plenty of it) and flavored by a mix of nuts, sugar, cinnamon, vanilla and lemon peel, which sounds prosaic until you taste it and wonder how six simple ingredients could make something that tastes so complex and provocative. Admittedly, the ingredient list looks a bit daunting at first glance, and you do need to start both the dough and the filling the day before you want your russenzopf, but most of that prep time consists of dough resting quietly in the fridge while you run your weekend errands or read the paper or untie your spouse or just take a little nap. There is a bit of rolling pin activity, but as long as you keep your work surface and your pin floured (be sure to brush off any excess flour on the surface of the dough before you fold it), it will roll out a treat. If you remember that the nut filling has to sit in the fridge overnight as well—I did not—then you will have a much, much easier time filling this than I did. 
Russenzopf
makes two loaves
For the Danish dough:
Detrempe
500g/scant 4 cups all-purpose flour
45g/3 generous tablespoons unsalted butter
57.5g/2 tablespoons + 1 ¼ teaspoons (or 2 ½ tablespoons!) granulated sugar
7.5g/2 3/4 teaspoons (or scant tablespoon) salt
11.25g/1tbsp active dry yeast (if you’re using instant yeast, use 10g/2 1/2 teaspoons)
100g eggs (about 2 large eggs)
200g/7 fluid ounces whole milk (Gina found she needed a whole 8-ounce cup to hydrate her dough properly)
Beurrage
375g/3 sticks plus 2 1/2 tablespoons unsalted butter
37.5g/2 1/2 tablespoons all-purpose flour
Either by hand or in a stand mixer, combine the detrempe ingredients and knead to moderate gluten development (about 3 minutes in a stand mixer, a little longer by hand). You don’t need a perfectly smooth, springy ball of dough, but it should be kneaded past the “shaggy” stage, to the point where it’s just starting to take on that springiness. Cover and refrigerate four hours.
Shortly before the dough is ready to come out of the fridge, make beurrage by pounding butter and flour together until they are amalgamated and form a rough 7"x 7” square. Butter should be cool and pliant, but not too soft. Remove dough from fridge and roll into a square. Roll edges out until they are long enough to cover the beurrage when it is placed in the center of the dough. (If you go to my Flickr page, the picture of this speaks much more eloquently than I do!) Incorporate the beurrage into the dough by folding the edges over the beurrage, then roll the whole thing into a long rectangle, approximately 4mm thick. Give the dough a single turn ( i.e. a “business letter fold”, or fold the top edge 2/3 of the way down the sheet, then lift the bottom edge to meet the fold on the top edge), roll again, give it another single turn, wrap in plastic and return to the fridge for about 1/2 hour, or until butter is rechilled and gluten relaxes a bit. Take it out and roll it again, give it a double turn ( i.e. a “book fold”, or fold the top edge to the middle of the sheet, fold the bottom edge to the middle of the sheet just below where you left the top edge, then take the bottom fold and lift it to meet the top fold), wrap well and let ferment overnight in the fridge.
For the filling (note: This must be prepared the day before you want to use it, and refrigerated overnight—sorry, Gina, I totally forgot this point! Thank you, PJ, for the reminder!):
150g/1 1/4 up to 1 1/3 cups hazelnuts, roasted, skinned and cooled (Gina says she only had 1/2 cup hazelnuts, so she swapped out almonds to make 1 1/3 cups, which, judging by her pictures, looks like a really, really good idea)
150/1 1/4 up to 1 1/3 cups walnuts, roasted
225g/1 1/8 cups granulated sugar
140g/1/2 cup (about 4) egg whites
7.5g/generous tablespoon (3 1/4 teaspoons) ground cinnamon (I used Vietnamese cinnamon from Penzeys, which was insanely good)
finely grated zest of one lemon
15g/generous tablespoon (3 1/2 teaspoons) vanilla extract
Grind hazelnuts and walnuts together with a little of the sugar, to keep them from turning to paste. Decant into a bowl, add other ingredients and mix. That’s it. It might take a little elbow grease to make it all come together, but it will. Cover and refrigerate overnight.
To assemble and bake:
Preheat oven to 425F and place rack in center of oven. Remove Danish dough from fridge and cut in half. Roll one half out to a 4mm rectangle, as you did during the rolling/turning of the dough. Spread half the filling (or less, if you prefer a lighter filling/crumb ratio) on the dough, keeping about a 1-inch border clear. Roll it up lengthwise, cut the roll in half lengthwise, and twist the halves together into a plait. (Be sure you can see some of the cut ends on the outside of the plait.) Place on either a parchment-lined baking sheet or in a buttered bread tin into which the loaf fits. Repeat with other loaf. Cover and let rise until dough just meets the top of the tin.
When risen, brush the loaves with an egg wash and place on the center rack of the oven. Bake for 15 minutes, then lower heat to 350 degrees and bake for an additional 35 minutes. Be sure to rotate the position of the loaves at least once, and keep an eye on them. The trick is to get them baked through without burning the bottoms. The bottoms will get a little dark, but if you catch them in time, they won’t scorch; they’ll just be very well caramelized.