Cook the broccoli in the vegetable stock for 10 - 12 minutes until soft.
Melt the butter in a second saucepan and add the flour while stirring vigorously. Then deglaze the roux with the cream and press in the garlic clove. Add the cooked broccoli with a skimmer. Also add 150 ml of the vegetable stock.
Puree until smooth with a blender and season with salt and pepper.