01 -
Preheat the oven to 375°F (190°C).
02 -
Evenly spread chopped rhubarb over the bottom of an 8x8 or 9x9 inch square baking dish or a deep-dish glass pie plate.
03 -
In a mixing bowl, combine 3/4 cup of the sugar, softened butter, baking powder, salt, vanilla extract, almond extract, milk, and sifted flour. Mix until smooth, adding a small amount of additional milk if batter is too thick to pour.
04 -
Pour the batter evenly over the rhubarb layer in the pan.
05 -
In a small bowl, stir together the remaining 1 cup sugar and cornstarch. Sprinkle this mixture evenly over the batter.
06 -
Gently pour boiling water over the entire surface. Bake at 375°F (190°C) for 45 minutes, extending baking time slightly if using gluten-free flour alternatives.