Preheat the oven to 375 º F.

Grease a 2 quart casserole dish with 2 teaspoons butter.

In a saucepan, combine the rhubarb, 2 cups sugar, 4 tablespoons of butter and lemon juice. Stir and cook until a syrup begins to form and the rhubarb starts to soften, about 6 to 7 minutes. Remove from the heat.

Using an electric mixer, cream the remaining 2 teaspoons butter and sugar together. Add the egg. In a small bowl, whisk together the flower, baking powder, cinnamon and nutmeg. Add the mixture to the creamed sugar and eggs in two additions alternating with the  vanilla, and buttermilk. Mix until thoroughly incorporated and the batter resembles a cake batter.

Pour the rhubarb into a greased 2 quart casserole dish. Spoon the batter over the rhubarb. Bake for 30 to 35 minutes or until the center is done.

Spoon a heaping serving of the cobbler onto a shallow bowl. Place one scoop of the ice cream to the side. Garnish with fresh mint and powdered sugar.