Garlic-stuffed Mushrooms

• 12 mushrooms
• 4 unbleached all-purpose fl
• 1 1/2 coarsely pecans (ground)
• 1 egg at room temperature
• 600 ml scalded milk
• 20 gr butter (unsalted)
• 3 gr parmesan cheese (fresh grated)
• 3 gr bread crumbs
• 2 slices scallions