Preheat the oven to 395°F (200°C). Add a glug of oil to your baking dish to coat the bottom and set it aside. Bring a large pot of very salted water to a boil, then reduce the heat to a simmer and leave it like that.
Make the chickpea bolognese: In a blender combine the tomatoes, chickpeas and parsley (and basil, if using). Pulse until the chickpeas are crushed and crumbly, but not completely mashed. You want the sauce to have texture.
Warm a skillet over medium-high heat. Add a tablespoon of olive oil, oregano and paprika. Cook for about 30 seconds or until fragrant, lower the heat to low and add the tomato chickpea mixture. Whisk in sugar, salt and nutmeg and bring to a simmer. Taste and season with more salt if it's bland and more sugar if it's too acidic for your taste. Let it on a low simmer as you do the rest.
Make the béchamel: Warm milk in your microwave or over the stove and set it aside, you need it very warm. In a small saucepan melt the butter. Immediately add the flour and whisk until you get a smooth paste. Slowly add the warm milk, stirring constantly.
Keep stirring and cook the sauce for about 5 minutes, until it thickens but is still spreadable. Season it with salt, nutmeg and few grinds of black pepper. Remove from heat.