Grease a 6-inch cake pan with butter.

In a food processor, combine the masa, sugar, salt, and baking powder. Start it on a low speed (I use the "Dough" setting on mine).

Through the feed tube, pour in the melted butter and half and half. Process just until a stiff dough forms, then turn off the food processor and scrape down the sides of the bowl.

Add the corn kernels and process in about five 1-second pulses, until the corn is incorporated into the dough but some larger pieces still remain.

Spread the batter into the greased cake pan. Cover the pan tightly with aluminum foil.

Make an aluminum foil sling (about 3 inches wide by 18 inches long) and place it under the pan.

Put the wire metal trivet and 1 ½ cups water in the Instant Pot. Use your aluminum foil sling to lower the pan of tomalito into the pot, and fold down the strips so they are not sticking up over the sides of the pot. Make sure the strips of the sling are not directly under the float valve -- there should be a clear path for steam to allow the pot to seal.

Cook on the Cake, Pressure Cook, or Manual setting for 40 minutes with a 10 minute natural pressure release. (The pot will take about 10 minutes to come up to pressure, and then the cooking program will begin counting down.)

Open the pot. Wearing heat proof mitts, use the foil sling to lift the cake pan out of the pot. Carefully uncover the pan, then use a cookie scoop to serve the tomalito or cut it into wedges. Serve the tomalito while it is warm -- it will set up and become more crumbly as it cools.