Pre-heat the oven to 175 ºC.
Grease with butter four ramekins or small cake molds of about 8 cm diameter.
In a bowl, melt the chocolate and the butter in the microwave, mixing with a spatula.
In a seperate bowl and with a hand whisk, beat the eggs with the sugar until it is incorporated.
Then, add the chocolate and butter mixture, continuing to mix with the hand whisk.
Carefully fold the flour into the mixture using the spatula.
Distribute the mixture across the flour ramekins, filling them about 3/4 of their capacity.
In each of the fondants, place about 25 grams of milk chocolate squares. Press them down until they are fully covered and in the center of the fondant.
Bake them for about 8 to 12 mins. Let the fondants cool slighty and then turn the ramekins over to serving plates. Serve with your favorite ice cream.