Preheat oven to 375°F. Lightly grease two oven-safe baking dishes with 1-cup capacity each or, alternatively, one baking dish with at least 2-cup capacity.

To make sauce:

Mix the sugars, cornstarch, and nutmeg together in a small bowl. Place rhubarb in small saucepan and add the dry ingredients. Stir in the orange juice and water. Bring mixture to a boil over medium high heat, stirring constantly and gently, being careful not to break up the rhubarb chunks. Reduce heat to medium-low and cook for 1 – 1½ minutes, just until mixture starts to thicken, continuing to stir constantly and gently. Remove from heat and stir in the butter and orange rind. If making two separate cobblers, divide the sauce between the two dishes or, alternatively, transfer entire sauce to one baking dish that has a 2-cup capacity.

To make the cobbler topping:

In small bowl, whisk flour, sugar, baking powder, salt, and nutmeg together. Stir in the orange rind. Cut in the cold butter using a small pastry cutter. Stir in the milk and incorporate ingredients to make a rough dough. Do not overwork dough. If making two separate cobblers, divide the dough in half and flatten each piece slightly and place on top of sauce. Topping does not have to completely cover sauce. If making cobbler in one dish, divide the dough into four portions and roughly flatten each portion into a circle and place on top of sauce. Sprinkle turbinado or granulated sugar over cobbler topping.

Place baking dish(es) on to a foil-lined baking sheet (in case of any boil-overs) and transfer cobbler(s) to oven. Bake for about 25 minutes or until sauce is bubbling and cobbler topping is lightly tanned. Let cobbler sit for about 15-20 minutes to allow it to set before serving. Serve plain or with a scoop of vanilla ice cream or a dob of whipped cream.