Preheat the oven to 425°F. In a frying pan, heat a bit of oil over medium heat. Add the onion and garlic and cook until slightly browned. Add the spinach and cook until wilted. Cool slightly, squeeze, drain and set aside. In a bowl, mix together the cream cheese, sour cream, half of the cheese (2 tablespoons) and the jalapeño. Stir in the spinach. Taste and season with salt and pepper. At this point you can put the dip into a oven-proof container, top it with the remaining cheese, wrap it and put it in the fridge for when someone comes over for nibbles, or you could go ahead and bake it off in some rolls. If rolling: scoop the filling into the rolls and top with the remaining cheese. Either way, bake on a lined baking sheet until the cheese is melted, bubbly and golden brown, 15-20 minutes. Enjoy warm spread onto pita chips, crackers or sliced baguettes.Note: this recipe is infinitely multipliable, so feel free to make a large vat and bake it off as you please.