This is adapted from the book Frida's Fiestas and you can clearly improvise beyond the basic recipe. Ground meat of some kind would be great but chayote are a mild, delicious vegetable and I wouldn't want to go to far from their original flavor. Take the chayote and cut them in half lengthwise. Steam them for about 30 minutes or until fork tender. Once cool enough to handle, scoop out the interiors and reserve, leaving a meaty cup for filling. Chop the scooped out chayote and add some tomato sauce, Oregano Indio and chopped black olives. Mix well and fill the chayote cups with the filling. Mix bread crumbs with crumbled cotija cheese and a little olive oil. You can use Parmesan if you like. Mix well and and top off each of the chayote halves. Heat in a 400F oven for about 10 minutes and then finish under the broiler for 5 minutes or until the tops are brown. Serve immediately. Notes: If you're unfamiliar with chayote, the whole vegetable is edible, even the cooked seeds and skin. They can be a little watery, so after scooping out the centers, rest them on a sieve and allow them to drain before mixing with the tomato sauce. A gentle push will help. I used black olives from our tree, which only gives about 2 cups of olives a year. I salt-cured them by packing them in sea salt in a Mason jar and shaking daily. After about three weeks, they're ready once rinsed. Another variation would be to add toasted black walnuts to the topping. I like this.