Cran-Raspberry Upside-Down Cake

This is a post-Thanksgiving creation.

I had a combination of the following, which would be hard to duplicate exactly but which could be varied quite a bit: about half a cup of canned (whole-berry) cranberry sauce, about half a small jar of homemade raspberry jam, and a cupful of fresh raspberries which needed to be eaten up quickly. I combined them in the bottom of a greased 8-inch square pan (gently messing them together) and also added a few Craisins just for a bit more fruit. I might also have added chopped apples or pears.

I started the oven preheating to 350 degrees, and put the pan full of fruit mixture into the oven to warm while I mixed the other ingredients. Some upside-down cake recipes have you put the batter on cold fruit, but I think they bake better if the batter goes on top of something that's already heated. (The same way dumplings work better on hot stew.)

I wanted the simplest, lowest-sodium muffin recipe I could find that would work as a cake, and settled on Apple Pie Muffins from 500 Low Sodium Recipes. I left out some of the spices and also reduced the amount of baking powder, from 1 tbsp. low-sodium baking powder to 2 tsp. regular (because I don't have any low-sodium). This is what I came up with:

1 3/4 cups all-purpose flour
1/4 cup sugar
2 tsp. regular baking powder (or 1 tbsp. low-sodium)
1 tsp. cinnamon
3/4 cup skim milk (I used 1%)
1 egg
1/3 cup vegetable oil

Mix the dry and wet ingredients separately and combine. Scrape over the heated fruit mixture, and bake the whole thing at 350 degrees for about half an hour or until the cake tests done and is just slightly browned. Serve warm, or cold for breakfast.