To a large bow add the flour and salt. Whisk while slowly drizzling in the milk until there are no lumps. Whisk in the egg. Refrigerate for 30 minutes.

Preheat oven to 425°F/220°C with rack in the center of the oven and place a CLEAN mini muffin pan in the oven to heat.

Once the oven is up to temperature, add a few drops of oil to each of the muffin tray cups and place back in the oven. Heat for 10 minutes until you just start to see the oil smoke.

Slide the oven rack out of the oven and carefully fill each cup halfway with the batter. Carefully slide the pan back into the oven and bake for 8-10 minutes until browned and puffed. Do not open the door before they are done.

Remove from the oven and place them on a cooling rack. When they are cool enough to handle, shape them so they are able to stand upright.

Take a little slice of roast beef and fill each one. Add a little horseradish sauce on top of each then add a little fresh dill. Serve immediately.