Earlier in the day: Cut cheese into fingers that will fit into chiles. Choose large, whole chiles and make a small slit on the side of each and carefully remove seeds and veins – kitchen shears make this task easy.
Carefully insert cheese fingers into each chile, pat dry and place on plastic wrap in freezer for about 30 minutes.
Heat oil in a deep fat fryer (best) or at least 1/2 inch deep in a pan or wok. Ideal temperature is 375° – shimmering and almost smoking.
Combine flour, salt, sugar and baking soda. In a cup, beat egg, add oil and cold water and beat to combine well. Combine with flour mixture and mix gently, DO NOT OVERMIX, a few lumps are fine. The consistency of pancake batter is ideal. For a thicker batter, increase flour. Masa flour may be substituted for some or all of the flour as desired.
Immediately after mixing, dip cold stuffed chiles into batter, allowing excess to drip off.* Carefully slide coated chile into hot oil, frying until golden brown on each side. Serve with green chile gravy and a guacamole salad.
*Notes: For an extra crispy relleno, sprinkle battered chile with Tony’s Tortilla Breadcrumbs, or seasoned panko crumbs.
Guacamole Salad Recipe
http://www.tonysmarket.com/common/recipes/StoreRecipe.asp?RecipeID=2087&storeID=5CB723477B4E43F88024DB82BE9E5BBF