I'm barely a PT baker, more like pick one holiday and follow a new recipe. We have some baking enthusiasts on here, so please help me!

Have you ever seem thick pieces of sugar on top of muffins and pie crusts? What kind of sugar is that? The sugar is thick like the brown raw sugar packets and it doesn't seem to melt in the oven.

Also, is a food processor necessary for mixing ingredients? I usually bake at my mom's house and use her Kitchenaid mixer, but neither of us have other "baker" gadgets.

Another thing, how long do you usually keep flour, corn starch, and baking spices around? I have items sealed, but most were purchased three years ago.