4 tablespoons softened unsalted butter, divided
1 cup milk, warmed to 110º F
1/3 cup water, warmed to 110º F
1/4 cup sugar
2 1/4 teaspoons active dry yeast (one envelope)
1 large egg
2 cups all-purpose flour
1 1/4 cups whole wheat or spelt flour
2 teaspoons salt
Chai Spiced Coating
1 cup light brown sugar
8 tablespoons unsalted butter, cool but pliable
1 teaspoon ground cinnamon
1 teaspoon ground ginger
1/4 teaspoon ground cardamom
1/4 teaspoon ground allspice
1 vanilla bean, seeds scraped
Use 2 tablespoons of the softened butter to generously grease a 10-inch bundt pan. Use your fingers to ensure that butter gets into every nook and cranny of the pan.
Combine the warm milk, water, sugar, and active dry yeast in a small bowl. Let sit until the yeast is foamy, about 5 minutes. While the yeast is proofing, combine the flours and salt in the bowl of a stand mixer fitted with a dough hook.
When the yeast is ready, turn the mixer on low and stream in the yeast mixture. Add the remaining 2 tablespoons of softened butter and the egg. Knead the dough until it is shiny and smooth, 6 to 7 minutes. The dough should be soft and sticky, but if it seems like it is overly wet, add more flour a few tablespoons at a time.
Coat a large bowl with oil or cooking spray and turn the dough into the bowl. Cover the bowl with a clean kitchen towel and set it in a warm place to rise until it has doubled in size, about 1 hour.
While the dough is rising prepare the chai spiced coating by mixing the spices and vanilla bean seeds into the sugar. Brown the butter by cooking it over medium heat in a small saucepan, stirring frequently until the milk solids turn light brown and the butter has a nutty fragrance. Set aside to cool slightly.
When the dough is finished rising, turn it out onto a lightly floured surface and pat it into a square about 8 inches by 8 inches. Use a pizza wheel or bench scraper to cut the dough into 32 pieces. (If you’re feeling ambitious, make 64.)
Working with a few pieces at a time, roll each piece of dough into a rough ball, then roll in the cooled browned butter followed by a roll in the brown sugar. Layer the dough balls in the bundt pan snugly. Repeat until all dough balls are used.
Cover the bundt pan with a clean towel and set it in a warm place to rise until it reaches 1 to 2 inches below the rim of the pan. This should take about 1 hour.
Preheat oven to 350° F. Bake the bread until the top is dark and caramelized and the sugar is bubbling around the edges, 25-30 minutes. Cool the bread in the pan for 5 minutes then carefully turn it out onto a plate. Cool for 5 more minutes then dig in. This bread is best served warm the day that it is made.