In a small bowl dissolve yeast in 1/4 cup warm water with a pinch of sugar. Let sit until slightly foamy.
In the bowl of an electric mixer, beat the yeast mixture, eggs, pineapple juice, 1/4 cup milk, sugar, vanilla and melted butter. When combined stir salt and flour into dough until a stiff batter is formed. Kneed for 10 minutes using a dough hook.
Cover and place in a warm place and let rise for 1 hour. When doubled, punch the air out of the dough and turn onto floured surface.
Divide into 2 equal pieces and then cut each piece into 8 sections for a total of 16 rolls. Form into buns forming them so that the seam is on the bottom and place in 2 buttered pie pans.
Cover and let rise again until doubled, about an hour.
Preheat oven to 350º. Bake for 15-20 minutes, then remove from oven and brush the tops with melted butter. To test if the rolls are done, tap the base of one, it should sound hollow.