In a large saute pan, melt 1 tablespoon of butter and sweat the onion. Add all the mushrooms and the remaining 2 tablespoons of butter. Season with salt and pepper and cook until mushrooms are soft. Add the milk and reduce by half. Add the provolone and melt. The consistency we're looking for is similar to that of a potpie.
On a buttered sheet pan layer two crepes. This way if the bottom one sticks you can still remove your "cake" from the pan. Spread a thin layer of the filling onto the crepe. Sprinkle a few chives on each layer. Top with another crepe and spread more mushroom filling on top. Repeat this method until you are out of filling. Top with another crepe and sprinkle on Parmesan. Place under broiler until Parmesan is melted and golden brown. Place onto a cutting board and slice into wedges. Serve immediately.
In a blender, combine all of the ingredients (excepting the butter for coating the pan) and pulse for 10 seconds. Place the crepe batter in the refrigerator for 1 hour. This allows the bubbles to subside so the crepes will be less likely to tear during cooking. The batter will keep for up to 48 hours.
Heat a small non-stick pan. Add butter to coat. Pour 1 ounce of batter into the center of the pan and swirl to spread evenly. Cook for 30 seconds and flip. Cook for another 10 seconds and remove to the cutting board. Lay them out flat so they can cool. Continue until all batter is gone. After they have cooled you can stack them and store in sealable plastic bags in the refrigerator for several days or in the freezer for up to two months. When using frozen crepes, thaw on a rack before gently peeling