Wash the potatoes, wrap in aluminium foil and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 1 1/2 hours. In the meantime, cut the bacon into strips, except for 2 slices.
Clean, clean and quarter the mushrooms. Heat oil in a coated pan. Fry the mushrooms and bacon for about 5 minutes until golden brown. Peel garlic, chop finely and add to sour cream. Clean and wash the radishes, dab dry and cut into slices.
Wash the chives, dab dry and cut into fine rolls. Set aside 1 teaspoon of chives rolls and 4 slices of radish for garnishing. Add the remaining radishes, chives, bacon and mushrooms to the sour cream and mix.
Season to taste with salt and pepper. Halve the remaining slices of bacon and leave them in the pan until crispy. Remove the potatoes, wrap them in foil and let them cool down a little. Meanwhile grate the cheddar roughly.
Cut the potatoes lengthwise in the middle and press them apart. Add the mushroom filling, sprinkle with chives and cheddar. Garnish with radish slices and crispy bacon.