Put the quinoa in a saucepan with plenty of water. Bring to the boil and simmer for 9 minutes. Drain in a fine sieve and leave to dry.
Meanwhile, put the broad beans in a pan of boiling water. bring back to the boil and then immediately drain in a colander. Refresh with cold water and leave to dry. if you are using ordinary, rather than baby, broad beans, you will need to remove the outer skin from each bean when cooled as they can be tough.
Remove all of the rind from the lemon with a sharp knife. Over a large bowl, slice between each membrane to remove each individual segment. Squeeze all of the juice into the bowl with the segments.
Peel the avocado and cut into chunks. Place in the bowl with the lemon segments and juice, ensuring each piece of avocado is coated in lemon juice.
Quarter the radishes
Crush the garlic. Add the garlic and cumin (if using) to the olive oil. Now stir the olive oil mixture into the quinoa.
Add the broad beans and radishes to the quinoa and mix in well.
Now add the avocado and lemon to the quinoa and mix in gently so as not to bruise the avocado.