Lamb Phyllo Rolls

• 12 phyllo sheets
• 2 ripe tomatoes
• 2 egg yolks
• 1 1/2 lamb (lean)
• 1 onion
• 120 gr myzithra cheese (fresh)
• 75 ml extra-virgin olive oil
• 60 ml meat stock (reduced)
• 50 gr butter (unsalted)
• 40 gr feta cheese (finely grated)