Cut 6 slices of pancetta into thick pieces. Place in a large frying pan and set over medium-high. Cook, stirring occasionally, until crisp, about 3 min. Add 1 tbsp (15 mL) olive oil, then 1 finely chopped shallot or 2 minced garlic cloves. Stir until shallot softens slightly, 1 to 2 min. Add an 8-oz (227-g) bag fresh spinach or 1 large or 2 small bunches, trimmed. Stir until wilted, about 3 min. Pan will be very full, so you may need to add spinach gradually. Squeeze 1 tbsp (15 mL) juice from a lemon overtop. Stir to mix.