Toast pine nuts - place in a dry skillet over low-medium heat, stir frequently until golden, about 3-4 minutes. Remove the pine nuts immediately from the pan and place on a heat proof plate to keep the nuts from continuing to toast. Set aside to cool.
Pesto - place basil, olive oil, cooled toasted pine nuts, garlic, salt, pepper and lemon juice in a food processor and process until all Ingredient are finely chopped. Scrape down the sides and process again to make sure all are incorporated. Add parmesan and process until smooth.
Sandwich - Turn on your oven’s broiler. Cut baguettes into 1/4 and slice lengthwise, spread pesto over baguette, add sliced tomatoes and cheddar. Place sandwiches on an oven safe baking sheet and put under broiler. Broil for about 3 minutes. Keep an eye on your sandwiches. Each oven is different and you may need more or less time to melt the cheese. You are looking for the cheese to melt and brown a bit but not burn.