1. To make the burger buns: Warm the milk and dissolve the yeast in it. Let sit for 5 minutes. Place the flour through salt into a bowl, pour the milk/yeast mixture in and mix together until the dough forms. Knead the dough until it is uniform and smooth. Put the dough in a bowl, cover with a damp cloth and leave in a warm place until doubled in size, which takes about 1 hour. Punch down the dough and turn out onto a lightly floured surface. Divide it into 16 small pieces and roll each piece into a small ball. Place the dough balls on a baking tray with baking paper underneath, cover with a damp cloth, and let the dough rise for about 30 minutes. Brush the dough balls with egg and sprinkle with sesame seeds. Cook them in the oven at 250° for 10-12 minutes.
2. Make the fried parsnips by cutting the parsnips into very thin strips with a peeler. Heat the oil in a saucepan. Test the temperature with a small piece of bread – bread should become golden. Fry the parsnips in the heated oil for approximately 3 minutes. Remove them with a slotted spoon and let them drain. Distribute the fried parsnips on a paper towel and sprinkle them with sea salt.
3. Stir the minced meat with salt and freshly ground black pepper. Form the meat into 16 small patties. Heat the butter in a pan over medium heat until golden. Cook the beef patties for about 1 and a half minutes on each side. Remove from the heat and keep them warm by covering the pan with a lid.
4. Assemble the burgers by cutting the buns in half, spreading chili mayonnaise on them, and layering with frisee salad, a beef patty, slices of avocado and shavings of Castello Mature Cheddar.
5. Serve with the crispy fried parsnips on the side.