The first time I tried this appetizer, it was really difficult to not keep the whole plate of them for myself and not share with the rest of class. A word of advice: make extra for leftovers the next day. You won’t regret it!
Preheat oven to 450 degrees. Toss sweet potato batons in cornstarch and half of the taco taco seasoning. Then toss the coated batons in the chipotle olive oil. Spread in an even layer on a parchment lined baking sheet. Roast for 5-10 minutes until the edges start to brown. Take out of the oven and flip. Roast again for another 5-10 minutes until soft and lightly browned. Potatoes will crisp further as they cool.
In the meantime, heat a grill pan over high heat until very hot. Slice the flank steak against the grain into 24 strips, about 1/8 inch thick. Season with salt & pepper and the other half of the taco taco seasoning. Lightly coat the pan with a bit of chipotle olive oil. Flash grill strips of steak, about 1 minute per side and remove from the grill. Wrap steak strips around three of the potato batons and poke through with a skewer. Top with chimichurri sauce.