blackberry jam cake

I too, have been baking. I have always wanted to make blackberry jam cake. It sounds so odd, and I was curious just what it would be. Well, it's a spice cake with jam added for, take your pick,
-color
-moisture
-a sweet/tart thing
-novelty.
I've read the recipe in Gourmet many times and thought I would just make that one. (the lazy sister)
I read over the recipe again and again, but the levener is hard to find. You don't add the baking soda with the dry ingredients, you premix it with butter milk and then add that alternating with the dry. Well, at first pass I couldn't find any levener. I assumed there was a mistake in the recipe and I would need to find something else. I went on line and found several recipes for blackberry jam cake. They all look more or less the same, just different sizes. By this time I had located the levener in the original recipe, so I went ahead with that.
I usually think food is too bland, so I pretty much doubled the called for spices. I also did this all sort of last minute, and ended up with the only seedless blackberry jam I could find at my local market. This was some country brand from KY, probably very authentic, but way too sweet as it turned out. Next time I'll hunt up some jam with a better sweet tart balance and/or add some lemon juice. I'll also bake at 350, not the 325 the recipe called for. The cake was a little hard and dry around the edges which I blame on the 75 minutes in the oven.
Finally I made the caramel icing, (brown sugar, butter and evaporated milk.) To this, I added about 3/4 tsp of salt. This was very good, even though you need a candy thermometer. I actually have one of those. There are dire warnings about over cooking and how rapidly it will "set up" as if you were working with some sort of quick dry cement. It didn't really set up until the next day, but I don't have that sort of patience when it comes to cake, so I poured it over while still runny. ("a bit runnier than you like it." "Oh no, I like it runny.") The icing, while delicious, ended up mostly puddled in the dish around the cake and I was forced to eat lots of it just with a spoon.
So next time, I'll bake at 350, use better quality jam, add the baking soda with the dry (just to see what happens) and make the icing while the cake is baking so both can cool together.
Naturally, next time the frosting will set up right away and I'll be faced with a week of chipping penuche out of a pot and eating it plain.
As for the blackberry jam-- didn't add color, not sure about moisture, no tartness. But there is that novelty, and you get to say, "Oh, its a blackberry jam cake."