This recipe is courtesy of Pastry Chef Rachel Going:

Before I get started with the recipe I’d like to say a word about butterscotch. When I close my eyes and think about the flavor of butterscotch, I taste the buttery, brown sugary, artificial vanilla sweetness of the bright mustard yellow, cellophane-wrapped hard candy that comes from the bulk candy section of the grocery store. To own the title of butterscotch, no other flavor will do. One might be surprised at how many recipes I tried to achieve this artificial flavor, using nothing artificial. But I think I got it. Except mine’s a little better.

Cinnamon Apple Butterscotch Sticky Buns

oven 375
makes 12 buns

1 recipe brioche dough (recipe follow)
1 recipe spiced cinnamon sugar (recipe follows)
1 recipe butterscotch sticky bun butter (recipe follows)
2 granny smith apples, chopped and caramelized in a little sugar
1/2 cup toasted chopped pecans
2 tbsp milk or cream

Prepare a 9×13 baking dish. I prefer glass for no particular reason. Smear the butterscotch butter evenly on the bottom of the pan, Sprinkle caramelized apples and pecans over the top of it. Set aside.

Roll dough on a well floured surface into a 14″ x 12″ rectangle. Brush the dough with the milk or cream and sprinkle evenly with the spiced sugar mix. Roll up from the long side, brushing off any excess flour as you go. Push in the ends so that the whole log is of even thickness. For ease of slicing throw it in the freezer for about 5 minutes. Slice into 12 even buns and lay cut side down in your prepared pan. Wrap loosely with plastic wrap and allow to rise in a warm place (75 to 85 degrees) until doubled in size. This should take about 1 1/2 to 2 hours.

Bake about 10 minutes before opening the oven. If, at this point you feel that they are getting too dark too quickly, you can cover them loosely with foil. Bake an additional 20 minutes. Allow the buns to cool about 5 minute in the pan before inverting them onto a serving plate or clean cutting board.

Brioche Dough (Note: This is a 2 day recipe, don’t try to rush it.)
from The Bread Bible by Rose Levy Beranbaum

Dough Starter: (Sponge)
2 Tbsp (1 oz) water, room temperature
1 Tbsp sugar
1/4 tsp instant yeast
1/2 cup (2.5 oz)unbleached all purpose flour
1 large egg

In a large bowl, combine all ingredients and whisk by hand for about 3 minutes, to incorporate air. The result should be the consistency of a thick, sticky batter. Scrape down the sides of the bowl, cover with plastic wrap, and set aside.

Measure out the ingredients for the flour mixture:

1 cup + 1 1/2 Tbsp (5.5 oz.) unbleached all purpose flour
2 Tbsp sugar
1 1/4 tsp instant yeast
1/2 tsp salt
2 large eggs, cold
1 stick (4 oz)unsalted butter, very soft

In a small bowl,whisk the flour, yeast, and sugar. Then whisk in the salt (this keeps the yeast from coming into direct contact with the salt, which would kill it). Sprinkle this over the top of the sponge, cover tightly with plastic wrap and let it sit for about 2 hours.

Scrape the dough into the bowl of a mixer, and add the cold eggs. Using the dough hook attachment, mix on low until the flour is moistened. Turn it up to medium and continue mixing for 2 minutes. Turn off the mixer, scrape down the sides of the bowl, and continue on medium speed for about 5 minutes or until the dough is smooth, shiny, and sticky. It will not pull away from the bowl completely. Add the butter one tablespoon at a time, waiting until each addition is completely incorporated before adding the next. The dough will be incredibly sticky, but don’t be tempted to add more flour. It will firm up when it’s chilled.

Scrape the dough into a lightly greased bowl and cover with plastic wrap. Let the dough rise until doubled in size, about 1 1/2 to 2 hours. Chill the dough for about an hour, or until firm. When chilled, scrape the dough onto a VERY lightly floured surface and deflate into a rough rectangle using the palms of your floured hands. Brush off any excess flour with a pastry brush and give the dough a business letter fold. Rotate the dough 90 degrees so that the closed side is facing your left. Give it a second business letter fold and round the corners. Wrap loosely but securely in plastic wrap, then place in a large freezer bag and refrigerate for at least 6 hours or up to 2 days…

Spice Sugar Mix
1/2 cup brown sugar
4 tsp cinnamon
1 tsp cardamom
2 tsp orange zest
1/4 tsp nutmeg
pinch salt

Combine all ingredients.

Butterscotch Sticky Bun Butter
3 1/2 sticks (14 oz) salted butter
2 cups (1#) packed dark brown sugar
1 vanilla bean, scraped
1/4 cup bourbon
juice of 1 lemon
1/2 cup sour cream
1 tbsp vanilla extract
1/4 cup Lyle’s golden syrup or corn syrup

Using the paddle attachment, in the bowl of a stand mixer beat butter, vanilla bean and sugar until creamy. In another bowl combine all ingredients. With the mixer on medium speed. slowly add the wet ingredients to the butter mixture. Beat until creamy and slightly emulsified. This can be made ahead and stored in the refrigerator for up to 5 days.