In a bowl, combine cheddar, cream cheese and mayonnaise. Beat with a hand mixer on medium speed until blended and fairly smooth. Stir in pimientos, scallions, garlic powder and cayenne. Cover and refrigerate at least 1 hour or overnight.
Heat broiler to high. Place baguette slices on 2 small baking sheets. Brush on both sides with oil. Toast under broiler (4 inches from heat) 2 minutes. Flip over and broil another 1 to 2 minutes.
Spread 1 heaping tablespoon pimento cheese on each toast.
