For the soup: In a large Dutch oven, heat the olive oil over medium heat. Add the jalapenos, onion, garlic, oregano, cumin, and chili powder, and sauté until golden, 4-6 minutes.
Add the vegetable broth, diced tomatoes, black beans, pinto beans, corn, and chopped chilies. Stir well, bring everything up to a simmer, and cook uncovered for 8-10 minutes.
Add the lime juice, and salt and pepper to taste. Stir in a small handful of chopped cilantro. If the soup seems too thick for your liking, add a bit more vegetable broth or water to thin it out. Add desired garnishes (ie. Tabasco sauce, lime wedges, chopped avocado, tortilla chips, shredded cheese, sour cream, chopped cilantro, etc). Serve along with the biscuits, and enjoy!
For the biscuits: Preheat your oven 375 degrees. In a large bowl, whisk together the dry ingredients and lime zest. Add the cold cubed butter to the bowl, and use your fingers to pinch the butter cubes into the dry ingredients until the mixture resembles damp sand, and the butter is the size of small peas.
Stir in the milk and shredded cheese until the dough starts to take shape and stick together. Be careful not to overmix at this stage, it should still look very rough.
On a clean surface, gently knead the dough until it starts to feel smooth and cohesive, about 1 minute. Pat the dough out to a ½ inch thickness, and use a biscuit cutter (or a water glass turned upside down!) to stamp out biscuits from the dough. The number of biscuits will depend on the size of your cutter.
Arrange the biscuits ½ inch apart on a baking sheet lined with parchment paper, or greased with a bit of butter.
Freeze the biscuits for 15 minutes (this ensures they turn out light and flakey). Brush each biscuit with a bit of the beaten egg, and sprinkle with a bit more cheese, lime zest, or sea salt if desired.
Bake for 12-15 minutes (depending on the size of your biscuits), until golden brown. Serve hot with extra butter if desired.