Heat oven to 425 degrees F. Brush 12 popover cups with 1 tablespoon melted butter. Place pan in oven 5 minutes.
Combine remaining 3 tablespoons butter, flour, milk, eggs, chives, dill and salt in bowl; mix well. Pour batter into preheated popover cups, filling about half full. Bake 25 minutes. (Do not open oven door during baking.)
Remove from oven; poke top of each popover with sharp knife to release steam. Serve warm with Butter with Canola Oil, if desired.