Paninis are extremely easy to make with an indoor grill/panini maker, and extremely delicious. I have a Cuisinart Griddler and love it for this purpose. Sometimes, nothing beats a panini. Especially one with homemade pesto, homegrown tomatoes, and fresh mozzarella. 
For my pesto, I always rely on this wonderful recipe by Simply Recipes. It is incredibly easy, but absolutely delicious. My take on making pesto is replicated below.
Ingredients
For the pesto
1 c. fresh basil leaves, packed
Our "herbs, beans, and greens" entry for Summer Fest 2010. Click the image to see what Summer Fest is all about!
1/4 c. freshly grated Parmesan-Reggiano or Romano cheese
1/4 c. extra virgin olive oil
1/6 c. pine nuts or walnuts
1 Tbsp. garlic, minced
salt and pepper to taste
For the panini
1 serving pesto (above)
2 ciabatta rolls
1 large tomato, sliced 1/4 inches thick
1 small or half of a large ball of fresh mozzarella, sliced into 1/4th inch thick wedges
10-12 basil leaves
pinch of salt (for tomato slices)
Directions
For the pesto
Combine all ingredients but olive oil and parmesan cheese in a food processor. Pulse several times to combine, then while food processor is running, drizzle in olive oil. Continue to process until mixture is to your desired consistency.
I generally add in the parmesan cheese last because I do not always eat all of the pesto I create at once. For any extra, it is very easy to freeze if you just leave the parmesan cheese out; then when you wish to eat it later, just defrost and add the parmesan cheese and it is ready to use right away. This has been very helpful for me when I have a lot of basil ready to harvest at the same time – plus we get to enjoy essentially fresh pesto all year round. In case you are interested in trying to freeze pesto, we’ve found that single-serving half-cup GladWare containers work great for holding the perfect amount of pesto for a meal for two.
For any pesto you intend to use immediately, add parmesan cheese at this time to the food processor, and again pulse a few times until well blended.
For the panini
Heat up your griddler, or other panini-making appliance, to medium-high heat.
Slice the ciabatta rolls in half lengthwise. Spread pesto on one side. On the other, layer mozzarella, then tomato slices. Sprinkle with salt. Top the tomato slices with the basil leaves. I know my picture at the left does not reflect this order, but given my experience, I recommend keeping the tomato slices in the middle to minimize the juices from soaking into the ciabatta bread… otherwise it does have a tendency to get a little soggy while eating.
Spray panini-maker with PAM, then cook each panini one at a time until the cheese just starts to melt and the top of the ciabatta roll starts to brown. Serve immediately.
Another easy way to freeze small servings of soup or pesto or sofrito – ice cube trays. Sometimes, we’ll then break out the cubes and store them in a tupperware for easy access.
Thanks ChiWei, good suggestion. We don’t do that because we have a freezer terribly laid out for holding ice cube trays if we want anything else to also fit in there, but for others that might work great!