Pistachio Buns

Ingredients

• For the filling:
• 7 1/2 ounces homemade pistachio paste, made from toasted pistachios
• 2 ounces unsalted butter, brought to about 70°F/21°C
• For the dough:
• 18 ounces all-purpose flour, plus more for rolling
• 2 teaspoons instant yeast, such as SAF
• 2 teaspoons Diamond Crystal kosher salt; for table salt, use about half as much by volume or the same weight
• 10 ounces homemade pistachio paste, made from toasted pistachios, brought to about 70°F/21°C
• 8 ounces plain, unsweetened Greek yogurt, any percentage will do, brought to about 70°F/21°C
• 4 ounces milk, any percentage will do, brought to about 70°F/21°C
• 2 ounces roasted pistachio oil
• 4 ounces blanched, peeled, and lightly toasted pistachios, or more to taste, optional
• For the frosting:
• 6 ounces heavy cream
• 2 1/2 ounces chilled homemade pistachio paste, made from toasted pistachios

Directions

1. Put the paddle on your stand mixer, add the pistachio paste and butter to the bowl, and beat until the mixture is smooth and creamy. Scrape the filling into a disposable pastry bag or small zip-top bag, using a flexible spatula to get as much as you can from the bowl. Wipe out the bowl with a paper towel and move on without washing it.
2. Use that same mixer bowl to whisk the flour, yeast, and salt until they are evenly mixed. Use a quart-sized liquid measuring cup for the wet mixture: add the pistachio paste, the Greek yogurt, the milk, and the pistachio oil, then mix by hand or with an immersion blender until everything is smooth and uniform. Pour it into the dry ingredients and stir until you have a shaggy dough that looks very dry. Switch to the dough hook and knead on low for about 25 minutes, until the dough is silky, elastic, and smooth enough that you can gently stretch a piece into a thin, rough sheet without ripping.
3. Cover the bowl with plastic and let the dough rise until it is doubled, puffy, and light, which takes about 2 hours at around 70 degrees F (21 degrees C). If the dough still feels dense, firm, or very springy, let it rest for 30 minutes before checking again. Dough has its own little schedule, so a warm kitchen will move things along, and a cool one will slow them down.
4. Tip the dough onto a lightly floured surface, flour the top, and roll it into a 13-inch square. Cut a corner off the filling bag, squeeze the pistachio filling over the dough, and spread it evenly with an offset spatula. Scatter on the extra pistachios, if you are using them, then roll the dough into a log and finish with the seam underneath.
5. Work an 8-inch piece of unflavored dental floss, thread, or butcher's twine under the center of the log. Bring the ends over the top, cross them, and pull tight to split the log into 2 pieces. Cut each half into 6 equal portions, then arrange them in an aluminum baking pan lined with parchment, 9- by 13- by 2-inch, or use 2 round cake pans that are 8-inch by 3-inch. Cover the rolls with foil and refrigerate overnight, or for up to 48 hours.
6. For the frosting, put the pistachio paste and cream in a measuring cup, blending container, or jar that just fits the head of an immersion blender. If the container is too wide, the cream will be too shallow for proper blending; if it is too narrow, the blades will not reach the paste at the bottom. You can use a food processor bowl instead. Process until the mixture turns thick and creamy, like frosting, watching the texture closely because the timing depends on your equipment. Scrape it into an airtight container and refrigerate until needed, up to 48 hours. You can also make the frosting while the pistachio buns bake.
7. Set an oven rack in the middle and preheat the oven to 350 degrees F (180 degrees C); while it heats, let the pistachio buns sit at room temperature. Bake with the foil on for about 35 minutes, until the buns are puffed and firm but still pale. If you are using darker pans, check them sooner. Remove the foil and bake about 15 minutes more, until lightly browned. Let the buns cool for about 15 minutes so the crumb can set, then serve each bun with a generous dollop of frosting.
8. Serve right away; these buns are not at their best after hanging around.