Day #1, to make the pastry:

1. Combine 2 cups flour, undissolved yeast, sugar and salt in a mixer bowl. Add milk and mix at low speed until blended. Mix in remaining 1 cup of flour. Fit the mixer with a dough hook and knead until a ball forms, about 1 minute. Cut the 2 tablespoons butter into small pieces and add to the dough. Continue to knead until butter is fully incorporated. The dough will become smooth on the surface and clear the side of the bowl in about 2 to 3 minutes. If dough is too sticky, add up to 1/4 cup additional flour, 1 tablespoon at a time. Place down in a bowl, cover with plastic wrap and chill for 1 hour.
2. Place 1-1/4 cups butter and 1 tablespoon flour in a mixer bowl. Beat until the butter is creamy.
3. Turn chilled dough onto a lightly floured surface. Roll to a 14 x 10-inch rectangle. Spread butter evenly over the bottom two thirds of the rectangle. Fold unbuttered third onto the middle third. Then, fold that onto the bottom third. Seal edges with the side of your hand.
4. Gently whack the dough with a rolling pin, starting at the center of the rectangle and working out. Then gently roll the dough into a 12 x 7-inch rectangle. Fold into thirds again (as above), handling carefully so the butter doesn't break through. If it does, sprinkle with flour. Fold rectangle in half. Place in 1-gallon size resealable plastic bag. Chill for about 45 minutes.
5. Remove dough from plastic bag. Again, gently whack chilled dough with rolling pin. Roll into a 14 x 10-inch rectangle. Fold the dough into thirds (as above) and then fold in half one last time. Place dough back in the plastic bag, seal and refrigerate overnight.

Day #2, To form and bake the rolls:

1. Mix the filling ingredients with a fork and set aside.
2. Line two baking sheets with parchment paper.
3. Whack dough several times, if necessary, while rolling chilled dough into a 16 x 12-inch rectangle, about 1/4-inch thick (lightly flour surface if needed). Spread the filling mixture evenly over the dough. Starting on the short side (the 12-inch side), roll the dough into a log. Gently pinch the seam to seal.
4. Trim ends with a very sharp knife. Cut the log into 12 slices. Place 6 rolls per baking sheet, about 2 inches apart. Flatten each roll to about 3/4-inch in height. Cover with a towel or plastic wrap and let rise until puffy (dough will not double), about 45 to 60 minutes. (Note: do not place rolls in too warm of an area or over hot water, or the butter may melt out!)
5. Whisk egg wash ingredients in a small bowl and brush on top and sides of each roll. Bake rolls in a preheated 400°F oven for 15 to 20 minutes, until a deep golden brown color all over. Switch pans to alternate racks half way through baking. (Note: if you can't fit both pans in the oven at the same time, place 1 pan in the refrigerator until the other is done baking.) Remove pans from the oven and let cool for 5 minutes. Slide parchment paper with rolls onto wire rack to cool. Allow to cool at least 10 to 15 minutes.
6. Melt white chocolate in microwave for about 45 seconds on HIGH (100%), then drizzle over tops of the warm rolls.

Make Ahead Tip: Cut rolls can be frozen for up to two weeks. Thaw at room termperature and bake according to directions above.