Dissolve yeast in a small bowl with warm water. Let sit for 5 minutes. In a large bowl, beat eggs, sugar, and salt. Add in yeast mixture. Add 1/2 cup flour and mix until smooth. Add melted butter and orange extract and mix well. Add remaining flour gradually and mix until dough forms. Add dough to a greased bowl and cover with a towel. Allow to rise until double in size (about an hour).