Spicy Noodles with Sweet Potatoes, Spinach and Tofu

peanut butter

rice vinegar

soy sauce

grated fresh ginger

garlic cloves, finely minced

brown sugar

toasted sesame oil

chili-garlic sauce (we used sambal olek)

large sweet potatoes, peeled and cut into 1/2" cubes (about 3 cups)

block firm tofu, drained and patted dry

package (10 ounces) soba noodles or whole wheat spaghetti

baby spinach (we used a whole cello bag from the grocery)

peanuts, roughly chopped

limes cut into wedges

sliced thai peppers and fresh cilantro (optional)

canola oil

kosher salt and freshly ground black pepper