Dissolve yeast into warm milk and let rest 5 to 10 minutes until foamy.
Stir in sugar, melted butter, eggs, red food coloring, and salt. Mix until glossy.
Sift in cocoa and gradually add flour until dough forms.
Knead on floured surface 8 to 10 minutes until smooth and elastic.
Place dough in greased bowl, cover and let rise 1 hour until doubled.
Punch dough down, roll into rectangle, spread softened butter, and sprinkle cinnamon sugar.
Roll tightly from long side, slice into 12 rolls.
Place rolls in greased dish, cover and rise again 30–45 minutes.
Pour broth or water into pressure cooker bottom as steam source.
Place rolls into pressure cooker insert or trivet and seal the lid.
Cook on high pressure for 30 minutes.
Let steam release naturally a few minutes, then manually open valve slowly before removing rolls.
Notes
Keep leftovers in an airtight container or wrap individually and refrigerate. Reheat gently with steam or microwave. Freeze for longer storage wrapped tightly in foil.