The 1/3-lb version goes for a pricey $6.99 in my area but I received this courtesy of Carl's Jr. Darius tried the Hardee's version but I thought I'd add my two cents.
True to the name, the El Diablo might be the spiciest burger I've had from Carl's Jr. I wouldn't say the habenero sauce was bacon-y, but it's creamy and slightly smoky with a substantial amount of heat that sets in slowly.
A bulk of the heat comes from an even layer of tangy, pickled jalapenos along the bottom of the patty. Additionally, they provide just a little of the watery crispness you might normally get from lettuce or tomatoes.
The pepper jack cheese was fairly mild and, like a lot of cheese you find in a fast food burger, it left a vague creamy feeling that actually offered a cooling effect here.
Combined, the four spicy ingredients were enough to induce sniffles and some milk-drinking, but not so much that I couldn't taste anything.
The bun was sweet with a wonderfully soft and airy quality that reminds me of brioche.
Overall, Carl's Jr.'s Thickburger El Diablo hits the right notes for heatseekers, but the flavors aren't enough to entice others to dip a toe into the spicy pool. Also, it's rather pricey and, beyond the bun and burger, I'm not sure the quality of the ingredients warrant the price (especially the bacon).
Nutritional Info - Carl's Jr. 1/3 lb. Thickburger El Diablo (356g)
Calories - 1050 (from Fat - 570)
Fat - 63g (Saturated Fat - 21g)
Sodium - 2440mg
Carbs - 79g (Sugar - 13g)
Protein - 37g