Remove all unpopped popcorn seeds and partially popped seeds.
Combine popcorn, cereal and pretzels in large heat proof bowl.
Combine brown sugar, butter, corn syrup and flour in pan and heat on stove until candy thermometer reads between 244 and 248 degrees (firm ball stage), stirring continually.
Immediately pour over popcorn and toss to coat.
Add M&M’s right away if making bars, otherwise wait till later in recipe.
Press into 15 X 10 X 1 inch buttered pan. Cool completely before cutting into bars.
Alternately; cook in oven on low heat (200) for 30 minutes, stirring occasionally.
Add M&M’s after the last stir so they do not break apart, but still will stick to the caramel.
Cool in a thin layer on waxed paper. Break into pieces before serving.
Recipe Notes
Optional: Replace pretzel sticks with sliced almonds and pecans.