Tuna tajine with onions

Ingredients :

 800 gr tuna
 3 beautiful onions
 1 c to s of flour
 1/2 glass of dried grapes (tempered in water the day before)
 1 c to c vinegar
 1 c to c of honey
 1/2 c to c of cinnamon
 1/2 c to c of cumin
 1/2 c to c of sweet chilli
 4 lemons
 1 or 2 c to s of olive oil