Preheat oven to 400 degrees. Cut bell peppers, onion, and jalapeños into large slices and place them on a baking sheet. Cut off the top of the garlic bulb and place them cut-side up on the baking sheet with the other veggies.
Drizzle olive oil over all the vegetables and garlic and roast at 400 degrees for 25-30 minutes.
Scoop out the roasted garlic from the bulb (it will be hot) and place in a blender or food processor with the other roasted vegetables. Add roasted tomatoes, paprika, canola oil, and salt to the blender and blend until smooth.
Combine the mixture with plain Greek yogurt (don't whip it together, just slowly fold it in) and add more salt if needed (we start with a few teaspoons and then add more to taste). For best results refrigerate in an airtight container overnight.
