Chargrill poblano peppers. Once charred, put in an airtight container to seam. When cooled, peel away skin and devein. Add to milk and warm on stove top. Do not boil. When warm, blend together with immersion blender. In a separate pan, melt butter. Then add flour, mix and saute until light brown. Slowly add this to the warm poblano mixture, whisking constantly. Then bring to a slow boil. Add salt to taste. Remove and cool in refrigerator. Once cooled, whisk in heavy whipping cream.
Sautee crabmeat with butter and fresh lime juice. Soften tortillas in warm oil in a pan. Smear each tortilla with mashed avocado. Add hot crabmeat and roll into an enchilada. Top with hot poblano sauce. Smother with shredded Monterey jack cheese and place in a warm oven until cheese is melted.