Boil the broccoli in plenty of salted water for 10 - 12 minutes.
Sauce preparation:
In a saucepan melt the butter in low temperature. Add the flour and stir well using a wooden spoon. Gradually add the milk and continue stirring. The sauce should become thick and smooth. Finally add the lemon drops and the salt and let simmer for 5 more minutes. Remove from heat and pour over the broccoli.