Peel the carrots and parsnips and cut them into quarters lengthwise.

Wash the leeks thoroughly and pat dry. Trim the bulbs and cut into rings.

Peel the onions and cut them into wedges.

Heat the butter in a large keep skillet. Add the leeks and red onions and stir to coat with the butter. Let cook until they become soft, Add the parsnips and carrots to the skillet. Season with salt and freshly ground pepper.

Then add the 1/4 cup water, toss to coat. Cover and simmer for 15 minutes.

Check the vegetables occasionally. If the pan becomes too dry and more water a few tablespoons at a time. Remove the vegetables from the heat.

Preheat the oven to 350 degrees F.

Wash the lemon half, pat dry and zest.

Rinse the thyme and separate the leaves from the stem.

In a separate bowl, whisk together the eggs and milk.

Grate the cheese and add it and the creme fraiche to the egg mixture.

Mix in the fresh lemon zest and horseradish.

Transfer the vegetables from the saucepan to a medium sized (approximately) 8 X 12 inch casserole dish. Pour the liquid over the top.

Place the casserole dish in the oven and bake for 30 minutes.

Remove and let cool 10 minutes before serving.