Steak Pasta with Creamy Sauce (in 30 minutes or less!)

Ingredients

• 350 g beef strips ((£3.50))
• 1 onion, finely diced ((£0.15))
• 3 cloves of garlic ((£0.39))
• 50 g pecorino ((£1.35))
• 500 g tagliatelle ((£0.75))
• 200 ml creme fraiche ((£0.89))
• Juice of half a lemon ((£0.30))
• Fresh parsley, finely chopped to serve ((£0.60))
• 1 tbsp olive oil
• 1 tbsp Dijon mustard
• Lots of pepper
• 400 ml beef stock
• 1 tbsp cornflour+ 2 tbsp cold water