I think I'm getting there. Not seeing a great deal of oven spring, but no more collapsing. I've switched to 8"x4" pans instead of the 9"x5", which seems to help. Also, got a good water sprayer for the oven. I tried a recipe for hamburger buns by Yvonne Young Tarr from The New York Times Bread and Soup Cookbook. The powdered milk and butter made for a softer bread. Did 9 buns and put the rest in a loaf pan.
Burger BunsTo make 20 buns
5 1/2 to 6 1/2 cupsflour
Two 1/4 oz. packages active dry yeast
1/3 cup instant nonfat dry milk
1/4 cup sugar
1 tbsp. salt
5 tbsp. butter, softened
1 1/2 cups hot water (120F to 130F)
Combine the dry milk, sugar, yeast, salt and 2 cups of the flour in a large mixing bowl. Cut in the softened butter. Stir the hot water slowly into the mixture, blending well. Beat for two minutes at the medium speed of an electric mixer, scraping the bowl from time to time. Blend in 1 cup of the remaining flour and beat for two minutes at high speed, stopping occasionally to scrape the bowl.
Make a stiff dough by blending in as much of the remaining flour as necessary. Knead the dough on a lightly floured board for eight to 10 minutes, or until it becomes elastic and smooth. Grease a large bowl and set the dough in it, turning the dough over to grease the top. Allow the dough to rise, covered, in a warm, draft-free place until it doubles in volume (approximately 45 minutes).
Using your fist, punch down the dough. Cover it and allow it to rise again for only 20 minutes. Before the dough doubles in size, cut it into two equal parts and divide each part into 10 pieces of equal size. Shape each piece into a ball. Flatten the balls into bun shapes and place them about 2 inches apart on greased baking sheets.
Let the buns rise once more, covered, in a warm, draft-free place until doubled in volume. This should take approximately one hour. Preheat the oven to 375F and bake the buns for 15 or 20 minutes. Slide the buns off the baking sheets and cool them on wire racks.
Next time, I'll try to shape the buns more uniformly. I put an egg wash on both the loaf and the buns (messy--I need a softer brush), and the seed mix is equal parts poppy, caraway and sesame, with a little coarse salt added. Getting there--I'll try adding some whole wheat flour next.