Spaghetti with frankfurter sausage

Ingredients

• 170 g. / 6 oz. sliced frankfurter sausages (2 sausages)
• 240 g. / 8.5 oz. of cooked spaghetti
• 1 onion cut into small squares
• 2 crushed garlic cloves
• 200 ml. / 6.76 oz. of crushed tomatoes
• Finely chopped tender garlic for garnish (optional)
• Salt and pepper to taste
• Olive oil