Cast-Iron Coffee Cake

Step 1 -Preheat the oven to 350 degrees F.

Step 2 -Line a 10-inch cast-iron skillet with parchment paper, then coat with nonstick cooking spray.

Step 3 -In a medium bowl, add the cinnamon, 1/2 cup of the flour, and 3/4 cup of the sugar and whisk to combine.

Step 4 -Use a fork to cut 1/3 cup of the cubed butter into the sugar mixture until coarse crumbs form, leaving some large pieces.

Step 5 -Cover the skillet and place it in the refrigerator. Let the crumb mixture chill until ready to use.

Step 6 -In a large bowl, add the strawberries, the rhubarb, and 1/4 cup of the sugar and let it sit at room temperature, stirring occasionally, until it has macerated, about 10 minutes.

Step 7 -In the bowl of a stand mixer fitted with a paddle attachment, add the remaining softened butter and the remaining sugar and beat on medium-high speed until it is fluffy, about 4 minutes.

Step 8 -Add the egg to the butter-sugar mixture and beat until it is combined.

Step 9 -In a medium bowl, add the baking powder, the kosher salt, and the remaining flour and stir until it is combined.

Step 10 -Alternate adding the flour mixture and the milk to the butter mixture, beginning and ending with the flour mixture, and beat with an electric hand mixer until it is well-combined.

Step 11 -Place a colander over a bowl. Add the strawberry mixture and drain the liquid. Discard or reserve the liquid for another use.

Step 12 -Fold the strawberry mixture into the batter mixture.

Step 13 -Pour the batter mixture into the prepared skillet and use a spatula to smooth out the top. Sprinkle with the crumb mixture.

Step 14 -Bake the cake until a toothpick inserted into the center comes out clean, about 50-55 minutes.

Step 15 -Transfer the skillet to a wire rack and let the cake cool, about 30 minutes.

Step 16 -Slice and serve.