Return the skillet to medium heat and add enough oil to cover the bottom of the skillet, about 3 tablespoons.
Toss in the sliced garlic and cook, stirring, for 1 minute.
Add half the spinach to the skillet. (It may seem to fill the skillet but don’t worry, it’ll cook down quickly.) Frequently toss the spinach, being certain to also toss the garlic so it doesn’t burn. Cook until the spinach begins to wilt.
Working quickly, immediately add the remaining spinach to the skillet and toss and stir until all the spinach has wilted. This will take around 5 minutes total if using baby spinach or up to 10 minutes total if using mature spinach.
Add the lemon juice and season with salt and pepper. Toss to combine.
Remove the skillet from the heat. Taste and, if desired, add more lemon juice, salt, and pepper.
Pile the spinach in a serving bowl, sprinkle over all or some of the bread crumbs, and serve immediately. (If not using all the bread crumbs, you can stash the rest in a sealed container in the fridge or freezer. Rewarm in a warm oven or a skillet over low heat before using to magically return their crunch.)