The gourd family, Cucurbitaceae, includes hundreds of vining plants that produce fruit, or curcurbits -- the most recognizable being pumpkins, winter squash, ornamental miniature squashes, and large gourds that are often hollowed out for birdhouses. The ornamental and hard-shell gourds are inedible; however, while the term “squash” is used to describe the edible fruit of the gourd family, and “gourd” refers to the inedible ornamental and hard-shell varieties, other cultures use the word “gourd” to include immature, edible varieties of hard-shell cucurbits. One in particular, the calabash squash or bottle gourd, is used in the cuisines of South Asia, East Asia, the Middle East, Central America, Africa and the Mediterranean. In India, bottle gourds are called "lauki" and are often cooked into curries.
Slice off the stem end of the gourd. Peel the gourd with a sturdy vegetable peeler, and cut it in half lengthwise. Scoop out the spongy pulp and seeds. Lay each half cut-side down and cut each into 1/2-inch slices. You can cut these in half again to make smaller pieces.
Chop the onion and tomatoes. Finely mince the ginger and garlic, and with the back of your knife blade, mash them into a paste. Heat the oil in a large pot over medium heat. Add the onions and saute them 5 to 7 minutes until they are soft and light brown. Add the chopped tomatoes, ginger and garlic, and mix well. Reduce the heat, cover, and cook until the mixture is very soft. Add the dry spices, mix well, and continue cooking for 1 minute.
Stir in 1/4 cup of water, cover, and let it simmer for another 5 minutes. Add the sliced gourd, salt, and just enough water to cover the gourd slices. Mix well, cover, and cook the curry for about 25 minutes, or until the gourd slices are tender and easily pierced with a fork. You may need to add more water as the curry cooks if it appears too dry.
Once the curry is done, remove the pot from the heat and stir in the ketchup. Before serving, garnish the dish with chopped cilantro. Serve the curry with the Indian flat bread called "naan," or over cooked rice.