1. I like to use 1 cup of cheese like tasty or cheddar for flavour and 1 cup of mozzarella for stretch! You can substitute with swiss, gruyere or any other melting cheese that has flavour and salt. You could also forgo the mozzarella and sub with another cheese.
2. I use ritz or other crackers to top the dip when baking to stop the surface from drying out and to add crunch. You can use any savoury cracker. You can also sub with panko breadcrumbs + grated parmesan (or just breadcrumbs + salt + drizzle of oil).
3. This dip is really best served warm so it's nice and creamy, or at least at room temperature. It becomes harder when cool. To make ahead, if not using a bread bowl, I mix it together but do not microwave. Then when ready to serve, microwave, give it a good mix then divide between bowls.
If using the bread bowl, use a sourdough cob bread like I did. You can assemble the dip in the bread per the recipe, then to reheat quickly, microwave the cob bread then bake to make it crusty. If you don't have a microwave, you will need to wrap the bread in foil and bake for 20 minutes, then unwrap and bake for 20 min (to make the dip warm in the middle).
If you don't have access to an oven for reheating, then bake the bread with the dip int it to make it crusty, let it cool then refrigerate. Then when ready to serve, microwave to reheat (if using sourdough, it stays pretty crusty even when reheated in the microwave).
4. Nutrition per serving, assuming 10 servings, excluding bread because I cannot be held responsible if you eat the entire bread bowl. This recipe makes around 4 1/2 - 5 cups of dip.