Step #1 Roast the bell peppers on a gas stove's open flame, turning them with tongs, until the skins are blackened, for about 2-3 mins; or roast them on a rack under the broiler 2 inches from the heat, turning them every 5 mins, for about 15 mins.
Step #2 Transfer peppers to a bowl, cover with plastic wrap, & let them cool.
Step #3 When cool enough to handle, peel peppers starting at the stem end, carefully cut off the tops with a paring knife, & rinse out any seeds.
Step #4 Set aside.
Step #5 Lightly coat a sauté pan with olive oil; place over med-heat/flame.
Step #6 Sauté garlic until it begins to turn golden, about 1 min.
Step #7 Add spinach; cook over med-heat/flame until it wilts, about 2 mins.
Step #8 Remove pan from heat.
Step #9 Stir in lemon juice & salt; place spinach in a bowl.
Step #10 Preheat oven to 350°.
Step #11 In a small pot, cook couscous according to package directions (about 5 mins).
Step #12 Using a spatula, add the couscous & the feta cheese to the wilted spinach, & mix well.
Step #13 Line a baking sheet with aluminum foil wrap.
Step #14 Generously stuff all the peppers with couscous-spinach stuffing, & place on a baking sheet.
Step #15 Bake on the center rack for about 8 mins.