Heat a frying pan over high heat until it is hot. Add the sesame seeds and stir occasionally. Watch them closely, and when they begin to brown lightly, which will take about 3-5 minutes, give them a final stir before turning them onto a plate to cool. When they are completely cold, store them in an air-tight glass jar in a cool, dark place.
Alternatively, preheat the oven to 160°C, 325°F, gas mark 3. Spread the sesame seeds on a baking sheet, and roast them in the oven for about 10-15 minutes or until they are nicely toasted and lightly browned. Allow them to cool and then proceed as before.