I’m not sure which soy butter they mean.
“Soy butter” could either mean a margarine made with soybean oil (which would be my guess as to what this means) or it could mean a peanut butter like product.
This recipe actually looks a bit more like nougatine (a harder caramelized sugar) than nougat (a chewy whipped sugar). But I’m not sure, because I’ve never made this before.
From a box sold in Chicago, Illinois.
Honey Nut Nougat
1/3 cup soy butter
1 cup raw sugar
1/3 cup honey
Melt the butter and add it to the sugar and honey. Cook about 15 minutes. Add 1 cup nut meats.
When cool and nearly stiff pour into buttered pan and cut into squares.