Stir 1 teaspoon sugar and yeast into cooled scalded milk and let sit for 5 minutes.
In a large bowl or a stand mixer fitted with the dough hook attachment, place flour, salt, yeast mixture, butter pieces, 1/3 cup sugar, 2 eggs,
zest and raisins, and mix until well combined. Knead until smooth and elastic, adding more flour, if necessary. Place dough in an oiled bowl, turning once to coat both sides, cover with greased plastic wrap and let rise in a warm place until doubled.
When risen, punch down dough and turn out onto a lightly floured surface. Divide into 3 equal pieces and let rest, covered, about 5 minutes. Roll each piece of dough into 3 ropes about 20 inches long and braid on a parchment-lined baking sheet, tucking
ends under. Instead of one long egg twist, the braid can be joined to make a circle shape. Cover with greased plastic wrap and let rise until doubled.
Heat oven to 375 degrees. Brush egg-milk glaze over entire surface of braid. Bake 50 minutes or until an instant-read thermometer registers 190 degrees. Let rest at least 20 minutes before slicing.