Heat olive oil in a medium skillet over medium-high heat.

Add thinly sliced onions to the skillet.

Reduce heat to medium-low.

Cook the onions for about 15 minutes, stirring occasionally, until very tender and almost caramelized.

Remove the skillet from the heat.

Heat a grill skillet over medium-high heat.

Add thinly sliced sirloin steak to the hot grill skillet.

Season the steak slices with salt and pepper to taste.

Cook the steak until desired doneness is reached, turning halfway through.

Remove the steak from the heat.

To prepare the Chimichurri Sauce, add garlic, Italian parsley, fresh thyme leaves, fresh oregano leaves, dried red pepper flakes, lemon zest, fresh squeezed lemon juice, red wine vinegar, and extra virgin olive oil to a food processor or blender.

Process the ingredients until smooth.

Place a spoonful of caramelized onions and the cooked steak strips in the center of a warm flour tortilla.

Drizzle generously with the prepared chimichurri sauce.

Sprinkle with Queso Fresco cheese crumbles.

For best results, warm the flour tortillas in the oven.

Wrap the tortillas tightly in foil.

Heat the wrapped tortillas at 350 degrees F for about 5 to 10 minutes or until warm.