Wash the red beets and cover generously with olive oil and salt.
Place in an oven dish with the rosemary and the garlic cloves, covered with aluminium foil.
Bake in the oven for four hours at 180°C. Remove the peel, slice and cut out circles.
Purée some of what's left over after the cut-outs with the remaining baking juice.
Set the rest aside for the red beet crumble.