Heat the oven to 425F with two rimmed sheet pans inside. Scrub the sweet potatoes, trim the tapered ends, and cut them crosswise into ½ inch rounds. You should get about 12.

Toss the rounds with the olive oil and salt until both cut faces are coated, then spread them on the hot pans with space between each round.

Roast 28 to 32 minutes, flipping once at 15 minutes, until browned at the edges and tender in the middle. Move them to a rack for 2 minutes.

Brown the ground beef in a skillet over medium-high heat, breaking it into small pieces, 6 to 8 minutes, until there are dark browned bits on the pan.

Drain off all the fat. Return the pan to medium heat and add the jalapeno, chili powder, cumin, smoked paprika, garlic powder, oregano, salt and water.

Stir 2 minutes until the spices coat the meat and the water has cooked off.

Scoop the avocados into a bowl and mash with a fork until chunky, leaving visible pieces. Fold in the lime juice, red onion, cilantro, garlic and salt.

Whisk the sour cream, chipotle powder, lime juice and onion powder together, then add the water a little at a time until it drizzles in a steady line.

Lay the warm rounds out on a serving platter in a single layer.

Spoon taco beef onto each round, keeping it inside the edge, then add a spoonful of guacamole on top of the beef.

Drizzle the chipotle crema over each one, finish with chopped cilantro, and serve with lime wedges. Build within 10 minutes of serving.