Mustard-Roasted Potato and Celery Root Timbale

2 russet potatoes, peeled and chopped into 1/2 inch cubes
2 garlic cloves, peeled
1 tablespoon whole grain mustard
1 celery root (celeriac), peeled and chopped into 1/2 inch cubes
2 leeks, white and light green parts only, sliced horizontally
2 tablespoons olive oil
salt and pepper to taste
a few leaves of mustard greens, washed and torn into small pieces
1/4 cup fresh, flat-leaf parsley, chopped
1/2 cup vegetable stock

Preheat the oven to 400 degrees F.

Toss the potatoes with the garlic cloves, mustard and 1 tb of the olive oil. Season to taste with salt and pepper and place the mixture in the bottom of a roasting pan.

Toss the celery root with the leeks and 1 tb olive oil. Season to taste with salt and pepper and place the mixture in the bottom of a roasting pan.

Roast potatoes and celery root for about 45 minutes, or until fork tender. Meanwhile, oil six ramekins and place a few pieces of the mustard greens in the bottom of each.

Once roasted, remove the vegetables from the oven and turn the heat down to 350 degrees F. Then separately puree each mixture with 1/4 cup of vegetable stock, and to the celery root, add the chopped parsley.

Spoon the potato mixture into the ramekins and, on top of that, the celery root mixture. Smooth out the tops and bake for 30 minutes until the tops have slightly browned. Turn the ramekins out onto plates and serve.