1) In a small saucepan, heat the olive oil over medium heat until a deep-fry thermometer registers 150°C. Remove from heat and allow to cool for 5 minutes.
2) Combine the garlic, parsley, basil, thyme, and spring onions in a small, heat-resistant glass bowl. Carefully pour the warm oil over the herb mixture, add the salt and pepper and mix well.
3) Spoon a thin layer of the herb mixture on the bottom of an 20 cm by 20 cm square glass baking dish.
4) Arrange the goat cheese slices in a single layer on top, then spoon the remaining herb mixture evenly over the goat cheese.
5) Cover the baking dish with cling film and refrigerate for at least four hours or overnight.
6) To serve: place the radicchio leaves on a serving platter, carefully place a slice of marinated goat cheese in each leaf and drizzle with additional herb mixture before serving.