One of my favorite Christmas dishes, but I dont know how yours are red. Mine are about as purple as purple gets.
She says ....
She puts Berry's in a pot ,adds sugar.
Then at the end ,lowers heat and adds cornstarch slowly.
Till it thickens to the consistency she wants.
She also says she has no measurements,just does it on the fly.
She said the cornstarch may be changing the color,but she doesn't really know.