Add sugar and yeast to the warm water and let it sit for 5-10 minutes to get foamy on top (I use the measuring cup - one less thing to wash!). If it does not foam, your yeast is bad and the dough will not rise.
In a food processor combine flour, lard/shortening and yeast mixture. Blend until dough forms a ball.
On a floured board knead dough until smooth and elastic, about 10 minutes. Divide dough into 12 balls.
filling
Combine all filling ingredients. And divide into 12 portions.
buns
Roll a ball of dough into a 2-3" circle with hands. Add one portion of pork filling, ¼ of an egg and a slice of sausage.
Pull dough edges to the top to surround the filling and pinch to close.
Place dough seam side down on a piece of parchment paper and place in a bamboo steamer with room for the buns to expand (about 4 per steamer tray). Repeat with all buns.
Cover with a towel and let rise until buns are doubled in size, about 1 hour.