Put the cake mix, oats, and pecans in a bowl and toss to combine well.
Melt the butter and drizzle the butter over the cake mix and stir well. It helps to use your fingers to combine everything into a coarse crumbly texture. Keep mixing until no dry flour remains. It will have a large rubbly crumble texture. Set aside.
Pour 4 cups rhubarb sauce into your 9x13 baking pan.
Sprinkle the crumble evenly over the fruit.
Bake for about 45-50 minutes, or until the crumble is starting to turn golden and the rhubarb is bubbling. Serve warm or at room temperature with whipped cream or ice cream.
Store leftovers at room temperature covered with foil. Consume within 3 days.
Nutritional information is provided as a courtesy and is an estimate only. This information comes from online calculators. Although The View from Great Island attempts to provide accurate nutritional information, these figures are only estimates.
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