Banh Mi, or bread filled with grilled pork, mayonnaise, herbs and a special spicy sauce which dance around all the flavors. Combined with a good cup of coffee and condensed milk (Vietnamese coffee),is the most popular street food for breakfast & brunch in Vietnam.
In Denver metro area, “Manna from Heaven” named the best food truck in 2012 based in the best Banh Mi in the city. 
http://www.westword.com/bestof/2012/award/best-food-truck-2118286/