Ingredients

• 8 Tbsp. chilled (1 stick) unsalted butter, cut into small pieces
• 1 cup all-purpose flour
• 1/2 cup packed brown sugar
• 1/2 tsp. ground  cinnamon
• 1/4 tsp. grated  nutmeg 1/4 tsp. salt
• 1/2 cup old-fashioned rolled oats
• 2 pounds (six large stalks) rhubarb, cut into 1/2-inch pieces (six cups)
• 1 tsp. grated orange  or grapefruit zest
• Juice of one orange or grapefruit
• 1 tsp. vanilla
• 1/2 cup granulated sugar
• 2 Tbsp. cornstarch

Directions

1. Preheat oven to 375 degrees. Whisk together flour, brown sugar, cinnamon, nutmeg, salt and oats. Mix in the chilled butter until mixture comes together into clumps.
2. In a large bowl, stir to combine rhubarb, zest, juice, sugar, cornstarch and vanilla. Pour rhubarb mixture into a small casserole dish and cover with the crumb mixture.
3. Bake until the rhubarb is tender when pierced with the tip of a knife, about 40-45 minutes. Serve warm (ideally over vanilla ice cream). Adapted from www.marthastewart.com.