First prep your vegetables. Make sure to keep them on separate plates. Finely dice your onion. Then quarter (longways) and chop the zucchini and yellow squash into 1/2in (1.25cm) thick pieces.
In a small pot, cover the corn and butter beans with 4 cups (.9L) of salted (1/2-1tbsp or 4.6-8.8g of kosher salt) water. Bring to a simmer until they are well cooked through, about 10-20 minutes. Test taste the beans, in particular, for doneness. Bigger ones can sometimes take a little longer. Then, strain and leave in the colander until they are ready to be added to the stew.
Next, whisk the tomato paste, marmite, ketchup, vinegar, soy sauce, brown sugar, and cornstarch together in a medium bowl. Once combined, set aside.
Drizzle the canola oil into a dutch oven or stock pot heated to medium high. Then add in your pepper and cumin for 15 seconds stirring until fragrant. At this point, toss in your onions and add a pinch of salt to bring out their moisture. After they start to sweat, add in the garlic and continue cooking until the onions are translucent.
At this point, add in the chopped squash. Sauté these until they just start to lose their rigidity but have not begun breaking down, about 7-10 minutes. They should still have a fairly bright color.
Add in the mixed sauce, corn, beans, diced tomatoes, chicken stock, pulled pork and bay leaves. Give the whole pot a good stir to incorporate and let simmer for about 60 minutes. Before serving, take out the bay leaves and stir in the vodka or tequila, if you are using it.