Line a 9x13 pan with tinfoil or parchment paper, leaving overhang over the edges.
Place the oats and rice krispies into a large mixing bolw, set aside until later.
Combine the butter, brown sugar and honey in a medium sized pot. Bring the mixture to a boil over medium-high heat, stirring constantly. Lower the heat and simmer until the sugar dissolves and the mixture is slightly thickened, about 2 minutes. Remove the pan from the heat : stir in the vanilla .
Pour the sugar mixture over the oats/rice krispies and fold with a rubber spatula until well combined.
Spoon into the prepared pan and press down lightly.
Sprinkle the M&M's over the top and press firmly into the tops of the bars. Make sure that the bars are tightly compacted in the pan.
Let set on the counter : do NOT refrigerate, it dries the bars out!
Remove the bars using the edges of the tinfoil and place onto a cutting board.
Cut into rectangles. Store the bars in an airtight container on the counter. These will last up to 5 days, an entire school week!