01 -
Preheat oven to 175°C (350°F). Line the bottom and sides of a 9 x 9-inch baking pan with parchment paper. Set aside.
02 -
In a saucepan, add chopped rhubarb, sugar, water, and lemon juice. Simmer on low-medium heat for 10 minutes until rhubarb is soft but still chunky. Set aside.
03 -
In a large bowl, mix flour, oats, sugar, and salt. Stir in melted butter until combined. Measure out 1/2 cup of the oat mixture and set aside. Press the remaining oat mixture firmly and evenly into the prepared baking pan.
04 -
Spread the cooked rhubarb filling evenly over the oat crust. Sprinkle the reserved 1/2 cup oat mixture over the top. Optionally, distribute it evenly or randomly across the top.
05 -
Sprinkle the top with cinnamon and sugar mix. Bake for 1 hour, until the topping is golden and the rhubarb filling is bubbling.
06 -
Let cool for at least 2 hours before cutting into squares.