Place 3 cups of rice Chex in two separate large bowls. Line two cookie sheets with wax paper.: When you separate the rice Chex into two bowls you will notice the cereal’s dry, toasty scent, which tells you it is ready to accept a chocolate coating without clumping. Lining cookie sheets with wax paper creates a nonstick surface so coated pieces cool cleanly, and it protects textures from tearing. A common mistake is skipping the wax paper, which makes removing coated Chex fiddly and messy; take the two minutes to line the sheets, and you will save time later.
Melt white chocolate chips in a microwave safe bowl for one minute on HIGH. Stir and continue heating for 30 second intervals until melted. If you're like me and can never get it to melt right, add a teaspoon or two of vegetable oil, stir, and continue melting. It should melt smooth. Immediately pour over one bowl of rice Chex and stir to coat. Spread on one of the wax-paper lined cookie sheets. Chill until hardened; about 5 minutes.: Right away you will smell the rich, sweet aroma of melting white chocolate chips , and the texture will transform from grainy to glossy as you stir. The intermittent 30 second bursts help avoid scorching, which can cause grainy chocolate. When you pour the chocolate over the cereal, move quickly to fold pieces so each one gets a thin, even coat; this helps them set into crisp clusters rather than heavy clumps. The chill firms the coating and gives a satisfying snap when broken. One common pitfall is overheating, which can cause the chocolate to seize into a thick paste, so pause and stir often for smooth results.
Repeat step 2 with the milk or semi-sweet chocolate chips and the second bowl of rice Chex.: As the second batch melts, you will notice the aroma is deeper and slightly less sweet than the white chocolate, and that contrast will be important in the final mix. Coat the second bowl with this milk or semi sweet chocolate so you have visual and flavor variety. Again, keep stirring and heat in short bursts to prevent burning. If the chocolate becomes too thick, a tiny teaspoon of neutral oil smooths it out, but only use a little to keep the coating crisp. Avoid rushing this step because uneven coating makes clumps that are either too dry or soggy when set.
While chocolate Chex is chilling, stir M&Ms and pretzels in a large bowl. Once chocolate and white chocolate covered Chex is hardened, break into pieces and add to the M&M pretzel mixture, then stir to combine.: At this stage the crunchy pretzels and colorful M&Ms create a lively scent of salted baked dough and candy, which contrasts with the cooling chocolate. Breaking the coated Chex into bite sized pieces makes distribution even so every scoop has cereal, candy, and pretzel. When folding everything together, use gentle movements to preserve the integrity of the coated pieces; aggressive stirring can shatter clusters and create crumbs. A typical mistake is adding the chocolate coated pieces before they are fully set, which melts the M&Ms or makes the mix sticky; wait until the chocolate is firm.
You can serve this in a big bowl or in individual bags. For individual bags: place 1 cup of mix into a fold-top sandwich bag. Fold closed and secure with a staple. Cut out the printable and fold in half. Secure to top of bag with double-sided tape.: place 1 cup of mix into a fold-top sandwich bag. Fold closed and secure with a staple. Cut out the printable and fold in half. Secure to top of bag with double-sided tape. : The final presentation step invites creativity, and the tactile act of filling bags feels festive. When you portion into individual bags notice how the mix settles differently than in a bowl; take care not to overpack so the candy remains visible and the pretzels stay whole. Using a staple and tape is quick, but ensure any adhesive does not touch the snack. One common issue is overfilling bags which leads to spills; use the one cup guideline for neat packages.