Beef Tenderloin Toasts with Horseradish Cream

12 very thin slices firm white sandwich bread

2 1/2 tablespoons unsalted butter, melted

1 tablespoon extra virgin olive oil

For Tenderloin:

1 teaspoon salt

1/2 teaspoon black pepper

1 pound center-cut beef tenderloin, tied

1 tablespoon olive oil

For Horseradish Cream:

1/2 cup chilled heavy cream

1 tablespoon bottled white horseradish

1/4 teaspoon salt

1/4 teaspoon black pepper

Peppery baby greens such as mizuna or arugula, for garnish