Heat a large skillet over medium heat. Add ground beef and chopped onion. Cook until the beef turns brown. Stir often to break lumps. Drain excess oil.

Add taco seasoning and water to the cooked beef. Mix well and simmer for five minutes. The mixture should become thick and flavorful. Turn off heat and set aside.

In a mixing bowl, add eggs, milk and biscuit mix. Whisk until smooth. Add salt and pepper. The batter should be thick but pourable. This forms the base.

Grease your baking dish lightly. Pour the batter into the dish evenly. Spread it well so it covers the bottom. This will create a soft crust.

Spoon the cooked taco beef mixture over the batter. Spread it evenly. Do not mix it with the batter. Keep layers separate for best texture.

Sprinkle shredded cheese over the beef layer. Then add crushed tortilla chips. This gives a crunchy texture and extra flavor to the taco pie.

Preheat your oven to 180°C (350°F). Place the dish in the oven. Bake for about 25 minutes until the top looks golden and set.

Remove from the oven and let it cool slightly. Add sour cream and salsa on top. Garnish with jalapeños or green onions if you like. Slice and serve warm.