In a large mixing bowl, whisk together 6 cups of flour, sugar, and salt. Reserve additional flour for kneading.
In a large mixing bowl, whisk together 6 cups of flour, sugar, salt, and the rapid yeast (2 1/4 tsp). Mixing the yeast directly into the dry ingredients ensures even distribution.
Add the 2 cups lukewarm water and melted butter (or shortening) to the dry ingredients. Mix until a shaggy dough forms.
Knead on a floured surface for 8–10 minutes (or use a stand mixer with a dough hook for 6–8 minutes), adding reserved flour as needed. The dough should be soft and slightly tacky but not sticky.
Place the dough in a greased bowl, cover, and let rise in a warm place until doubled in size (about 1 hour).
Punch down the dough, shape into loaves or rolls, and place in greased pans. Cover and let rise again until doubled (about 30–45 minutes).
Bake at 375°F for 25–30 minutes for loaves or 18–20 minutes for rolls, or until golden brown and the internal temperature reaches 190°F.