6 tablespoons
cold salted butter, cut into small pieces
¾ cup
brown sugar
½ cup
all-purpose flour
¾ teaspoon
ground cinnamon
¼ teaspoon
ground nutmeg
½ teaspoon
sea salt
½ cup
rolled oats
For Serving
Whipped cream (optional)
Vanilla ice cream (optional)
Method
Preheat the oven to 375°F with a rack in the center position. Grease a 9 x 9-inch baking dish with cooking spray.
In the prepared baking dish, toss the rhubarb with the sugar, lemon zest, lemon juice, and mint, if using. Spread the mixture into an even layer.
In a food processor, combine the butter, brown sugar, flour, cinnamon, nutmeg and salt. Pulse for about 30 seconds, or until pea-size clumps form. Add the oats and pulse until incorporated, 2 to 3 more times.
Scatter the oat topping over the rhubarb mixture. Bake until the filling is bubbling and the topping is browned, about 40 minutes.
Serve warm alongside ice cream or whipped cream, if desired.