Hi, Jan. I remember exactly what you are asking about. The mixes were from the 1950s and they were called "Py-O-My" pudding cakes. The cake rose to the top and the pudding stayed on the bottom. My mom used to make them too. Can you believe that this actually stuck in my mind all these years? I have two recipes -- one for chocolate fudge pudding and one for lemon, both out of a Betty Crocker cookbook from the 1960s. The lemon cake pudding can also be lime, orange or pineapple and I'll give instructions at the end for these options. I make these often because they go together so easily. The ingredients for the fudge pudding cake are assembled in steps, rather than all mixed together like a traditional cake. Here you go:

Hot Fudge Pudding Cake

Step 1:
1 cup all purpose flour
2 tsp baking powder
1/4 tsp salt
3/4 cup sugar
2 Tbsp cocoa
1/2 cup milk
2 Tbsp shortening, melted (I have used butter)

Step 2:
1 cup brown sugar (packed)
1/4 cup cocoa

Step 3:
1 3/4 cups hot water

Heat oven to 350 degrees F.

Blend flour, baking powder, salt, sugar and 2 Tbsp cocoa in bowl. Stir in milk and shortening or butter. Spread in square pan, 9 x 9 x 1-3/4. Sprinkle with mixture of brown sugar and 1/4 cup cocoa. Pour hot water over entire batter.

Bake 45 minutes. Either cut into squares and invert on plates or invert entire pudding on platter. Serve warm.

Lemon Cake Pudding

1/4 cup all purpose flour
1 cup sugar
1/4 tsp salt
1 Tbsp grated lemon rind
1/4 cup lemon juice
2 egg yolks, well beaten
1 cup milk
2 egg whites, stiffly beaten

Heat oven to 350 degrees F.

Blend flour, sugar and salt in mixing bowl. Stir in lemon rind and juice, egg yolks and milk.

Beat and fold in egg whites. Pour into 1 quart baking dish. Set in pan of hot water 1 inch deep.

Bake 50 minutes. Makes 6 servings.

Lime Cake Pudding
Make Lemon Cake Pudding except in place of lemon use lime juice and rind.

Orange Cake Pudding
Make Lemon Cake Pudding except in place of lemon use orange juice and rind.

Pineapple Cake Pudding
Make Lemon Cake Pudding except reduce the sugar to 1/2 cup, use only 1/2 cup milk, only 1 Tbsp lemon juice. Add 1/4 cup drained crushed pineapple and 1/4 cup pineapple juice.

I've never made the pineapple version, but if you try it please let me know how it works out. Buon Appetito!