This cake is denser than birthday cake and more flavourful too (brown sugar and cinnamon are good like that). Plus, it's covered in fruit! That means you can practically eat it for breakfast. Not that I did that, or anything.
If you (or your grocery store) are against plums, any stone fruit — cherries, peaches, nectarines, and apricots — will work. Play around with zests and spices accordingly.
1 1/2 cups all-purpose flour
2 tsp. baking powder
1/4 tsp. salt
1/4 tsp. ground cinnamon (or cardamom)
pinch freshly-grated nutmeg (optional)
5 tbsp. margarine
3/4 cup light brown sugar, packed
2 eggs (or your favourite vegan replacement)
1/3 cup canola oil (or safflower oil)
zest from 1 lemon (or orange)
1 1/2 tsp. vanilla extract
1. Preheat your oven to 350°F (make sure a rack is centred first). Line an 8-inch pan with parchment paper and grease the parchment paper and any parts of the pan that it doesn't cover. Dust with flour and tap out the extra. This will all make your life so much easier later. (The best kind of pan to use is square. I did not have a square pan though, and it turned out fine.)
2. In a smallish bowl, mix the flour, baking powder, cinnamon, and salt.
3. Using an electric mixer or a fork and willpower, beat the butter at medium speed (or, if using your arm, quickly) until it's creamy. Add the sugar and beat for three minutes. Add one egg (or half the egg replacement) and beat for a minute. Add the other egg and beat for another minute. On the same speed, add the oil, zest, and vanilla. (If you are doing this by hand, keep going through the burn. Think about how it will improve your sex life or something.) The batter should look smooth. On low speed, add the dry ingredients, and stop mixing as soon as everything's combined.
4. Use a spatula to get all the batter into the greased pan and then smooth down the top. Place the plums, cut-side up, in the batter. If you have a square pan, just do it in rows, leaving a little space between each plum. If you have a circular pan, start with an outside ring and then fill in the middle. If you shake the pan lightly after, the plums will settle a little.
5. Bake for 30 to 40 minutes. It's kind of hard to tell when it's done, but the plums really need to be cooked through without the cake getting too hard. Also, the batter closer to the plums will take longer to cook. If the batter far away from the plums is cooked, check near (or under) them with a toothpick. The batter will be light brown and a knife in the centre should come out clean.
6. Let the cake sit for 10 minutes in the pan, and then run a knife around the edges. Have two plates ready. Put one plate upside down on top of the pan, get a firm grip, and flip everything over. Lift the pan off and remove the parchment paper. Place the second plate upside down on top of the cake, and flip everything again, so the cake is the right way up on the plate. Cool. The cake will technically keep for about two days, wrapped, at room temperature, but will probably not take that long to finish.
Adapted from Smitten Kitchen.