Mix together crabmeat, cornbread, spinach, pine nuts, mustard and salt and pepper. Lay fish skin side up and top with 2 1/2 ounces stuffing. Roll tightly and refrigerate until set. Dredge in seasoned flour, dip in buttermilk, and roll through fish fry mix. Deep fry at 350 degrees F until light brown. Remove to sheet pan and finish in a preheated 350 degree F oven until temperature of 150 degrees F. Top with 1 1/2 ounces cajun beurre blanc and garnish with lemon.
In heavy saucepan, add all ingredients except butter and cream. Reduce the liquid over low heat. Add heavy cream and reduce by half. Slowly add butter, whipping continuously-alternating pan on and off flame. Strain and add seasoning.