Pastina-stuffed Avocados

• 2 ripe but firm avocados
• 2 tomatoes (fresh)
• 1 pastina
• 475 ml chicken stock
• 120 ml vinaigrette
• 16 gr onion (diced)
• 7 gr parsley (fresh)
• 1 gr saffron threads
• 2 slices green onions