Place a medium pot over medium heat. Add the butter, shallots, garlic, and jalapeno.
Saute for 3 to 4 minutes to soften, then add the half and half and chipotle peppers.
Whisk in the cornstarch. Allow the mixture to come to a simmer, so the half and half can scald (not necessary with evaporated milk) then lower the temperature to medium-low.
Stir in the cream cheese and mustard.
Slowly start adding the shredded cheese.
Stir and add by the handful, until the sauce comes together. if you prefer your cheese sauce a little thinner, add an extra splash of half and half. Serve immediately, or keep warm in a slow cooker or fondue pot.