Activate yeast by mixing warm milk, yeast, and a pinch of sugar. Let sit for 5-10 minutes until foamy.
Mix flour, remaining sugar, cocoa powder, and salt in a large bowl. Add yeast mixture, melted butter, eggs, vanilla, and food coloring.
Knead dough for 5-7 minutes until smooth and elastic. Place in a greased bowl, cover, and let rise for 1-2 hours until doubled.
Roll dough out into a 15x9 inch rectangle. Spread softened butter over the surface and sprinkle evenly with mixed brown sugar and cinnamon.
Roll up tight from the long edge and cut into 12 rolls using dental floss. Place in a greased baking pan.
Rise again for 30-45 minutes while preheating oven to 350°F (175°C).
Bake for 25-30 minutes. Meanwhile, beat cream cheese, butter, powdered sugar, and milk to make the glaze.
Frost the rolls while warm and top with heart sprinkles.
