Bring the water, milk, and salt to a boil. Slowly whisk in the polenta. Turn heat to low and continue whisking for five minutes, or until polenta is smooth and creamy. Remove from heat. Dish some polenta into your serving dish layered one inch thick. Mine are served individually so a short clear glass works great. Then, smooth out the rest of the polenta on a cookie sheet about a 1/2 inch thick.
Combine minced tomato, minced red bell pepper, minced serrano pepper, and minced white onion in a small bowl. Squeeze the lime juice on top of these ingredients and stir until well combined. I call this confetti! Set aside.
Remove excess water from grated zucchini by squeezing the moisture through a paper towel. Heat butter in a skillet over medium heat. Add diced onions and zucchini into the skillet and saute until onions are cooked through. Season with salt and pepper to taste. Once the mixture is done cooking, put in a small bowl and set aside.
In the same skillet, heat up refried black beans, adding a little water to thin out a bit. Season with salt and pepper to taste. When heated thoroughly, remove from heat and layer on top of the polenta in glasses about one inch thick.
Layer the zucchini and onions on top of the beans.
With a circle cookie cutter, cut out 4 circles of the polenta from the cookie sheet. Add the circled polenta cakes on top of the zucchini and onions.
Thinly slice the avocado and add a slice on top of the circled polenta cake.
Add a couple of the monterey jack shavings on top of the avocado.
Add a small dollop of the Mexican crema on top (or beside) the monterey jack and avocado.
Sprinkle the confetti on top to garnish and serve!