Add the egg, flour, melted butter, milk, water and salt to a blender.  Blend on low for about 15 seconds.  Scrape down the sides to ensure all the flour is incorporated.  Blend for an additional 15 seconds.  Place the blender in the refrigerator for at least 30 minutes to let the bubbles in the batter subside.

After the batter has been in the refrigerator for about 15 minutes preheat the oven to 350° and coat a 9x13 baking dish with cooking spray or melted butter.

Melt 2 tablespoon butter in a medium sauté pan over medium heat.  Add garlic and cook for 1 minute.  Add chicken, ½ cup wine, broth, tarragon, salt and pepper.  Cover and cook until chicken is done, about 8 minutes.

When chicken is cooked through remove chicken from the pan and cut into bite-sized pieces.  Set aside.

Reduce the heat to medium-low. Add flour to the pan and mix to form a roux (a thick paste-like sauce).  Slowly add the remaining wine, stirring until smooth.  Add the creme fraiche and stir until combined.  Add the mushrooms and chicken to the pan.  Stir to combine mixture.  Turn off heat and leave the pan on a warm stovetop while you prepare the crepes.

To make the crepes, butter a crepe pan or small non-stick skillet and heat over medium-high heat.  Pour ¼ cup of the batter into the pan.  Tilt the pan so that the batter coats the surface evenly.   Cook for 2 minutes until the edges begin to lightly brown and curl up.  Carefully remove crepe from pan and repeat with remaining batter.

To assemble the crepes, add about ¼ cup of filling the center of a crepe.  Roll the crepe around the filling and place into the prepared baking pan.  Repeat with remaining crepes and filling.

Once all the crepes are in the pan, sprinkle with grated gruyere and bake for 15 minutes.  Remove from oven and serve immediately.