1) Preheat oven to 350 degrees Fahrenheit.
2) For beef filling add oil to a medium skillet over medium heat. Add onions, garlic, and jalapeno. Cook for a few minutes until veggies soften. Then add beef and seasonings and continue to cook until beef is cooked through, about 8 minutes.
3) Stir in cilantro and Cotija cheese and remove from heat.
4) For veg filling, add oil to a skillet over medium heat and add mushrooms and a pinch of salt. Cook until mushrooms loose their moisture and soften. Then add other veggies and cook until soft. Stir in cilantro, cheese, and season with salt and pepper. Remove from heat.
5) To make the taquitos add 1/4 cup of neutral oil to a small skillet over medium heat. Add one corn tortilla to the pan and cook for 10 seconds per side. Remove from pan and lay on a clean surface.
6) Spoon two tablespoons of filling into the center of the tortilla and roll it into a tight cylinder. Place rolled taquito on a baking sheet lined with parchment paper. Repeat until all taquitos are made.
7) Bake taquitos for 20 minutes at 350 degrees Fahrenheit until they are crispy on the outside.
Serve taquitos immediately with sour cream, salsa, and guacamole. Leftover taquitos can be reheated in the oven for 10 minutes at 350 degrees.