Cut circles out of bread slices w/2inch round cutter.
Melt 3 tbsp butter in small saucepan.
Brush both sides of bread circles lightly w/butter.
Bake bread circles on ungreased baking sheet 5 to 6 minutes per side until golden.
Remove to wire rack.
Increase oven temp to 425°F.
Melt remaining 2 tbsp butter in small saucepan.
Stir in flour; cook and stir over medium heat until bubbly.
Whisk in milk; cook and stir 1 minute or until sauce thickens and bubbles (sauce will be very thick). Take off heat, and add mushrooms to sauce, 3 tbsp cheese, salt and black pepper, and stir until well blended.
Spread heaping tbs mushrooms mixture on top of each toast round; place on ungreased baking sheet.
Sprinkle remaining 3 tbsp cheese over canapes, dividing evenly.
Garnish w/black and green olive slices, and bell peppers.