Making the savory and the sweet masa is slightly different. Before mixing the masa ingredients, put the corn husks for tamales to soften in hot water for 30 minutes.
To make savory masa into a bowl, add the masa harina, baking powder, and salt. Mix the dry ingredients and pour vegetable broth slowly. Once the masa gets consistency, add the vegetable oil and keep mixing. You'll feel that's lighter than tortillas' masa. It'll be ready when you can close your fit, and it slides through your fingers.
Cover with plastic wrap and let it sit while making the sweet masa.
Put the masa harina, baking powder, salt, and sugar into a bowl. Then mix the dry ingredients and add milk and water. Now integrate all the components and then add melted unsalted butter. Just like savory masa, grab a ball and close your fist. If it slides through your fingers, it's done. Save some sweet masa aside to make the oreo tamales.
Take the corn husks out of the water and wipe them dry and clean. To build the tamales extend a husk on a clean surface. Remember to add the masa to the smooth side, not the rugged one. Use a spoon to make a thin and uniform layer of masa, making a rectangle. Follow this procedure for both sweet and savory tamales.