Preheat the oven to 375F. Smear an 8-inch baking pan or cake tin with a pat of butter, then set aside.
Wash the plums and dry them with a clean kitchen towel or paper towel. Then cut it in half and take the pit out, then set aside.
1 lb plums,
In a medium bowl, whisk softened butter and sugar on medium speed until light fluffy.
⅔ stick unsalted butter,, ½ cup brown sugar
Add eggs one at a time and whisk to combine.
2 large eggs
Add the rest of the dry ingredients and wet ingredients, except for the sliced plums, and stir with a spatula.
⅓ cup milk,, 2 cups almond flour, ½ cup regular flour,, ½ tsp cinnamon, ¼ tsp salt, 1 tsp baking powder, 1 tsp vanilla extract
Transfer the prepared batter to the baking dish and spread evenly using a spatula or the back of a spoon.
Place the plum slices on top of the cake batter, pushing them in slightly then sprinkle with 1 Tbsp of sugar.
1 lb plums,
Place the plum cake in the preheated oven. Bake for 40-45 minutes until it's golden brown or until the toothpick inserted in the center comes out clean.
Remove the cake from the oven and let the cake cool then serve warm on a cake plate and enjoy.
Notes
Nutritional calculations for this recipe were calculated for regular flour, not gluten free rice flour.