Marinated Beef Fillet with a "Brilliant" Potato & Horseradish Cake

Ingredient List
Beef Fillet
tenderloin, steak (rib-eye or fillet mignon) or 2lb roast
sea salt & freshly ground pepper
2 handfuls fresh rosemary sprigs
1 bulb of garlic, broken up, cloves left whole w/skins on
5 tbs extra virgin olive oil
kitchen twine/string
1-2 cups of red wine (amount, according to your preference)
2 tbs - 1 stick of butter (again, depending on your preference)
Potato & Horseradish Cake
3lbs red potatoes, peeled & sliced (1/4" thick)
3 tbs creamed horseradish
2 tbs extra virgin olive oil
fresh dill, (optional)

Prepare your beef with the marinade.  First, season the fillet with salt and pepper (be generous). In a pestle and mortar (or food processor) bash up a quarter of the rosemary with a clove of garlic and make a paste. Add 5 tbs of extra virgin olive to the paste and rub all over the beef.  Tie the beef up with 4 pieces of string then poke the rosemary sprigs under the string.

Preheat the oven to 450 degrees. Put the beef aside and let the marinade soak in for a few minutes.  Now, get ready to prepare your potato cake. 

Parboil your sliced potatoes in boiling salted water for 5 minutes. Drain in a colander and transfer to a bowl with just enough olive oil to coat the potatoes. Season with salt and pepper.  If using fresh dill, you can also add that to the mix. Use a non-stick cake tin and place half of the potatoes into the tin or pan, smearing the creamed horseradish on top.  Place the rest of the potatoes on top and pat down. Put the potatoes in the oven on the bottom shelf.

Once the potatoes are in the oven, brown the beef in a snug fitting roasting tray until all sides are browned.  Add the garlic cloves to the tray, place the beef on top of them and put in the oven on the top shelf.  Cook the beef for 20 minutes.  After 20 minutes, turn the beef over, baste it, and add the red wine and butter to the tray. 

After 25 minutes of cooking, remove the potato dish then carefully place a clean tea towel over it and push down to compact the potato slices into a nice tight cake.  Put the potatoes back into the oven for another 15-20 minutes.

Cook the beef to your preference. Remove the beef from the oven, but continue baking the potato cake for 5 minutes, or until it appears golden on top.

When ready to serve, remove the string from the beef and the rosemary sprigs.  Carve the beef into slices.Save any juices from the meat and return them to the tray, with the red wine and butter. Finish by squeezing the garlic cloves, then pass through a sieve onto the meat. 

Turn the potato cake out onto a board or just scoop it out and divide among the plates.