One of those dishes, and I'm stealing a quote here from a friend, that qualifies as "where-have-you-been-my-whole-life?" good. It warms your soul and is a quintessential Sichuan dish that will likely skyrocket to one of your favorites for a quick dinner if you have chili oil on hand. That perfect mix of salty/savory/spicy with some great texture contrast will make any of your non-tofu-loving friends and enemies change their mind.
Sichuan mápó tofu is almost exclusively defined by its use of a deliciously deep fermented broad bean and chilies, Pixian doubanjiang. Of all primary uses, I immediately think of mápó tofu, it is that quintessential to me as an ingredient. High quality Pixian doubanjiang will look like a thick, slightly dry, red miso-like consistency and will be chunky as it should be as minimally processed and ground into a paste. Some semi-domestic brands (Lee Kum Kee) will come as a much more oil-laden sauce, which are still good, but may not deepen to as dark of a red as a true dry Pixian doubanjiang.
Don't be afraid to experiment with your own comfort level with the amount of chili oil - most of the red color should come from the fried doubanjiang, which imparts a much more subtle, rich heat rather than overloading with straight chili oil.
Prep (well ahead of time):
Make some Sichuan chili oil. A link can be found HERE. You can also use your favorite chili crisp.
Thinly slice ginger (very thin julienned strips is good), thinly slice the garlic and shallot, chop the whites of the scallion. Chop greens for garnish/adding at the end. Run your knife through the yá cài to make sure there aren't any huge chunks.
Cube tofu, and (optionally) gently blanch for a minute or two in salted water if using medium-firm tofu.
Preheat a dry wok (or straight walled saute pan) over Medium-High heat until lightly smoking.
In the hot wok, toss the neutral oil in, swirl oil up the sides of the wok, and start frying the beef until it is well crispy and has broken up (4-5 minutes over medium-high heat). The more crumbly the texture, the better - reminder that you are looking for beef flavor, not to have beef as the center-stage texture (this is a tofu dish after all). Using a fine mesh spider, remove the beef from the wok (or you can just push it to the side of the wok).
In the reserved oil over a medium heat, add the doubanjiang and fry until the oil has turned a deep red. If it starts to blacken and char, ease off the heat immediately as this will make the dish bitter. After 2-3 minutes, add the ginger, shallot, garlic, and whites from the scallions.
After 30 seconds, add the stock, Shaoxing wine, soy, Chinkiang vinegar, and reserved ground beef.
Gently toss tofu into your now simmering red stew of deliciousness, GENTLY mixing to combine. Try not to smash everything up, it ruins the aesthetic, but keep periodically stirring to prevent sticking.
Now, while this is simmering, is also when you want to add chili oil to your desired spice level. Or you can totally leave it completely on the side for anyone to add at the table. Just remember that you can always add more spice but cannot take it away.
After a few minutes at a simmer, the dish is basically ready - you can keep it over low heat as you prepare the rest of the meal (steaming/blanching green vegetables like gai lan or bok choi, making jasmine rice, etc). Immediately before serving (and over medium heat), swirl in about half of your potato starch slurry to thicken. Potato starch should make the sauce go glossier than a more common corn starch, but you also don't want to overdo the thickening agent - you should still be able to pour it like a thick stew, not as a congealed clump.
Take the wok off heat and stir in the reserved chunks of scallion greens - you're looking for these to just wilt in the sauce, not completely be cooked to death.
Top with some more finely chopped scallions and serve with jasmine rice, some green vegetables, extra chili oil, and happiness.