Place the cleaned, dethorned cactus pieces in a small saucepan, and cover with water.  Boil cactus until the pieces turn from bright green to dull green. Drain and discard water, and rinse away any goo that the cactus naturally releases. (*If you are using the jarred nopalitos, they are already cooked so you can skip the cleaning and cooking steps entirely.) 

Heat oven to 425°F (218°C) Warm the vegetable oil (shortening or drippings) in 10” (25cm) oven proof skillet to approximately 300°F (148°C.) 

Meanwhile, combine the corn meal, flour, sugar, baking powder and salt in a mixing bowl.  Add the egg and milk, combining well with an electric hand mixer. Stir in the corn and cooked nopalito bits. 

Pour the mixed batter into warmed skillet of vegetable oil and place in the preheated oven. Bake for 20-25 minutes, or until a wooden pick inserted in the center comes out clean. 

Cool briefly but serve warm.