Step 1

Preheat oven to 350°F. Generously grease an 8-inch square baking pan.

Step 2

Combine the brown sugar, water, butter, and salt in a small saucepan. Bring to a boil over medium-high heat, stirring occasionally.

Step 3

Set aside to cool.

Step 4

Whisk together the flour, baking powder, cinnamon, and salt. Set aside.

Step 5

Using an electric mixer on medium speed, beat the butter and sugar until light and fluffy.

Step 6

Reduce mixer speed to low. Add the flour mixture in 3 portions, alternating with 2 portions of milk. Add the vanilla with the first portion of milk. Mix just until combined.

Step 7

Transfer the batter to the prepared pan, and spread evenly.

Step 8

Pour the topping mixture over the batter.

Step 9

Carefully transfer the pan to the oven. (The pan will be very full of liquid.) Bake for 45 to 50 minutes, or until the cake is set. The center of the cake should not jiggle when the pan is gently shaken.

Step 10

Cool the cake in the pan on a wire rack for 15 minutes.* Then, invert the cake onto a serving platter. If any topping remains in the bottom of the pan, simply scrape it onto the cake and smooth the top.

Step 11

If desired, sprinkle pecans over the top of the warm cake. Serve warm or at room temperature.