Flank Steaks with Shallot and Tarragon Pesto

Heat butter and 1 tablespoon of olive oil in a medium skillet over low heat. Add shallots, season with salt and pepper, and cook for about 30 minutes, until shallots are tender and caramelized. Transfer shallots to the bowl of a food processor with tarragon, cheese, and ⅓ cup of olive oil and blend until smooth. Season with salt and pepper, to taste.

Meanwhile, place a grill pan over medium-high heat. Rub steak with remaining tablespoon of olive oil and grill for 6 to 8 minutes per side, until a golden brown crust forms and meat is cooked through. Transfer steak to a cutting board and let rest for 10 minutes. Slice steaks against the grain and transfer to a platter. Spoon pesto over top and serve.