Rhubarb Upside-Down Cupcakes

Step 1
Preheat oven to 350 degrees F (175 degrees C). Coat 18 muffin cups with cooking spray.

Step 2
Spoon 1 teaspoon melted butter into each prepared muffin cup, followed by 1 Tablespoon brown sugar and about 2 Tablespoons rhubarb. Use a muddler or the back of a wooden spoon to press it into an even layer.

Step 3
Bake in the preheated oven until rhubarb just begins to soften, 7 to 8 minutes.

Step 4
Meanwhile, beat cake mix, water, eggs, oil, and almond extract in a large bowl with an electric mixer at low speed until moistened, about 30 seconds. Increase speed to medium and beat for 2 minutes.

Step 5
Pour batter over rhubarb in hot muffin cups, filling each just over 3/4-full.

Step 6
Return to the oven and bake until a toothpick inserted into centers comes out clean, 18 to 20 minutes.

Step 7
Cool in the muffin cups 5 minutes before inverting onto a wax paper-lined cooling rack. Serve warm drizzled with any syrup in cups.