Pat the tofu dry with paper towels—removing excess moisture is the key to a proper sear—and season with salt and pepper.

Heat a portion of the vegetable oil in a large nonstick skillet over medium-high heat until the oil shimmers. Add the tofu and cook until browned on all sides, about 8 to 10 minutes, then transfer to a plate.

Add the remaining oil to the same skillet and sauté the mushrooms until they have softened and their moisture has evaporated, about 5 minutes.

Stir in the chili-garlic sauce, garlic, and ginger and cook until fragrant, about 30 seconds, keeping the aromatics moving to prevent the garlic from scorching.

Add the vegetable broth, cider vinegar, soy sauce, and sugar to the skillet. Increase the heat to high and bring the liquid to a simmer.

Add the ramen noodles and cook, stirring occasionally to separate the blocks, until the noodles are tender, about 3 minutes.

Remove the skillet from the heat and stir in the spinach and the browned tofu. Let the dish sit for a minute until the spinach is just wilted and the tofu is warmed through, then serve immediately.