Step 1

Combine the gluten-free flour, white sugar, cinnamon, kosher salt, and butter in the bowl of the stand mixer fitted with the paddle attachment. On a medium speed mix together until the streusel topping comes together and starts to form clumps. Transfer the Streusel topping to a small bowl and place in the refrigerator until ready to use. Use the same mixing bowl to make the plum cake batter. No need to wash it.

Step 2

Preheat the oven to 350F. Lightly spray the spring form with nonstick cooking spray and line the bottom with parchment paper. Set aside.

Step 3

Using a paring knife, split the plums in half.

Step 4

To the mixing bowl add the white sugar and the lemon zest. Using your hands, rub the zest into the sugar.

Step 5

Add the gluten-free flour, baking powder, kosher salt, and ground ginger. Add the room temperature butter, eggs, and vanilla extract. Starting at a low-speed mix until a dough forms. Increase the speed to medium-high and mix for 2 minutes. Stop the mixer halfway and scrape down the sides of the bowl.

Step 6

Transfer the gluten-free plum cake batter to the prepared spring form and with a small offset knife, spread it out evenly. Place the halved plums cut side up on top of the batter slightly pressing them into the gluten-free plum cake batter. Top with all the streusel.

Step 7

Bake at 350F for 55-60 minutes. The top of the cake will be golden brown and a toothpick comes out clean.

Step 8

Remove the cake from the oven and allow to cool for 10 minutes on a cooling rack before removing the ring from the springform pan.

Step 9

Cool cake completely or serve while still warm.

Step 10

To serve dust with powdered sugar.