1) To make the dough: Mix and knead everything together — by hand, mixer or bread machine set on the dough cycle — to make a smooth dough. If you're kneading in a stand mixer, it will take about 5 to 7 minutes at second speed; the dough should barely clean the sides of the bowl, perhaps sticking a bit at the bottom. In a bread machine (or by hand), it should form a smooth ball.
2) Place the dough in a lightly greased bowl. Cover the bowl, and allow the dough to rise, at room temperature, for 1 to 2 hours, or until it's nearly doubled in bulk. Rising may take longer, especially if you've kneaded by hand. Give it enough time to become quite puffy.
3) While the dough is rising, lightly grease a 9" x 13" pan.
4) To make the glaze: Whisk together the syrup, melted butter, and maple flavor, if you're using it.
5) Spread the glaze in the prepared pan. Sprinkle the brown sugar (or maple sugar) and toasted walnuts atop the glaze. To toast walnuts, see tips, at left.
6) Transfer the dough to a lightly greased work surface, and pat or roll it into a 16" x 12" rectangle. It's a nice, soft dough, and pats out easily.
7) Sprinkle the maple sugar evenly over the dough, leaving an uncovered strip about 1" wide along one long end of the rectangle. Gently pat it onto the dough, so it adheres.
8) Starting with the sugar-covered edge, roll the dough into a log the long way.
9) Using a sharp or serrated knife, slice the log into 20 slices. Or, instead of using a knife, loop a length of dental floss around the log, and pull the ends in opposite directions; they'll slice nicely through the dough.
10) Space the buns in the pan; five rows of four works well. Cover the pans, and let the buns rise until they spread out, touch one another, and puff up, about 1 1/2 to 2 hours.
11) Towards the end of the buns' rising time, preheat the oven to 350°F.
12) Bake the buns for 25 to 30 minutes, until they're a light golden brown and feel set when you poke them.
13) Remove the buns from the oven, and loosen their edges with a knife. Carefully — the syrup is hot! — turn them out onto a rack (set over parchment, to catch any spills) or parchment-covered sheet pan. Scrape any glaze that may have stuck to the pan onto the warm buns, and spoon any glaze that's run onto the pan back onto the buns.
14) Serve warm, or at room temperature. Wrap any leftovers airtight, and store at room temperature.
Yield: 20 sticky buns.