Break the noodles up into small pieces. Boil the noodles till done about 4-1/2 minutes boiling.

Set aside all the contents of the seasoning packets.

Melt the butter and add milk. When the milk is hot, do not boil, enough to melt the cheese add the extra sharp cheddar cheese. Lower the heat.

Add the noodles and stir well. Add the seasonings stir in well

Add in the mozzarella cheese stir well still never let this boil, or the sauce will break.

Mix the 1/3 cup milk and cornstarch.

Make sure the noodles and liquid is hot it's ready

Now add in the cornstarch solution and stir in well stirring constantly for it will indeed thicken.