Beef Tenderloin without wine

1 ounce dried porcini mushrooms 1 cup hot water 2 tablespoons butter 6 tablespoons olive oil, divided 1 small red onion, finely chopped 1 teaspoon finely[...]

1 tablespoon Dijon mustard 1 1/2 teaspoons horseradish 1/4 teaspoon dried basil 1/4 teaspoon dried thyme leaves 1/4 teaspoon dried tarragon leaves 1/4[...]