Scald 1 cup milk (heat to steaming). In a mixing bowl combine warm milk, yeast and sugar. Let yeast start to bubble, about 5 min.
Add 12 tbsp butter and eggs to mixer and beat, with the paddle attachment, until slightly blended. Stir in flour and salt, about 2 min. Scrape down sides of bowl and continue mixing on medium speed to develop the dough, 3 min more.
Transfer dough to a greased bowl and cover with plastic wrap; set aside in a warm place and let rise until doubled, about 1 hr. Grease tow large-cup muffin tins. Melt 6 tbsp butter and stir in 1½ tsp maple extract; set aside.
Gently punch down dough and divide in half. Roll into 2 12-by-18-inch rectangles on a lightly floured work surface. Spread maple-butter mixture evenly over both rectangles. Sprinkle each with half the brown sugar and walnuts. Roll tightly into logs, starting at the long edge, and pinch seams together. Cut each log into 6 3-inch pieces for a total of 12 buns. Place in muffin tins cut side up, cover and allow to rise for 30 min. Heat oven to 325°F Bake until golden brown, 28 to 30 min.
Combine caramel topping and 1½ tsp maple extract. carefully remove hot buns from pan and place on a clean baking sheet; drizzle with caramel.
For icing: Melt 3 tbsp butter and stir together with confectioners' sugar and 2 tbsp milk; drizzle over buns. Serve warm or cool. Store airtight for up to two days.
To make 18 standard-size buns:
Grease 18 standard-size muffin tin cups. Fill and roll dough as directed. Cut each log into 9 2-inch pieces. Place cut side up in muffin tins, cover and let rise 30 min. Bake as directed, 22 to 25 min.
Prepare buns as directed, in either size. Do not let rise a second time; cover pan, freeze until solid, then keep frozen in pan or transfer frozen buns to a zip-to bag. To bake, thaw in pan and let rise at room temperature until double in size, 2 to 3 hr. Bake as directed.
These babies freeze! You can make them large or standard size and freeze them unbaked for up to 3 months. Pull them out 2 or 3 hours before baking and bam! you have breakfast, brunch, or a little nibble for a baby shower spread.