Have been making this for about 40 years. One of my daughters all time favorites. Enjoy!
In a large bowl big enough to hold a whole angel food cake inside, mix jello according to directions, MINUS 1/2 cup of cold water, until all jello is completely dissolved. Pour strawberries into jello. Place cake upside down into bowl, pushing down into jello/strawberries mixture, holding down with your hands for a few minutes, giving the cake a little time to absorb some of the liquid. Take something heavy enough to hold down cake almost completely in jello and place on top of cake in bowl. I usually use a few heavy plates that fit inside the top of the bowl well, about the size of the cake. Or if your bowl has a tight fitting lid that will hold your cake down in the jello, use that. Refrigerate until firmly set, I refrigerate mine until the next day. To release cake, fill sink with warm water, hold bowl down in water, making sure not to let it get in the bowl, for about 1 minute. Place large plate over top of bowl and invert, hold for a few seconds, if cake doesn't fall to plate, hold in water a few more seconds, repeat until cake falls out onto plate when inverted. Serve with whipped cream if desired.