Cook pasta in medium or large pot according to packaging. Strain and set aside.

(OPTIONAL) Dice small onion and brown in small pan. Cook bacon (if needed) and chop. Set both aside for later.

Prepare American cheese into small cubes. (Can also get this from the deli sliced, which makes it easy to crumble in your hand during the heating process.)

In warm pot used to cook pasta, heat evaporated milk over medium heat, just until it starts to bubble then immediately turn heat down to low. Start whisking to prepare for melting process.

Slowly add American cheese in batches. Whisk continuously during the melting process. (Very important to keep stirring!)

Add shredded Colby Jack in batches (this will melt much faster - again don't stop whisking!)

Add all spices once cheese is melted through and sauce begins to thicken. (If it thickens too much, add a heavy splash of milk and continue whisking until all mixed through.)

(OPTIONAL) Add cooked onion and bacon to cheese sauce. Mix through.

Remove from heat or turn heat down to "warm". (Don't leave sauce on the heat too long without stirring as you risk the cheese burning to the bottom.)

Add pasta and mix thoroughly.