Preheat the oven to 350F.
Heat olive oil in a large skillet over medium heat. Once oil is hot, add the ground beef, breaking it up with your cooking utensil then let the beef brown, stirring occasionally, for about 6-8 minutes. When the beef is almost done, stir in your taco seasoning until everything is well coated. Remove from heat.
Steam your frozen butternut squash according to the package instructions. Once it’s cooked, transfer the butternut squash cubes to a blender or food processor then puree until smooth. Add in 1/4 cup plain greek yogurt then puree again until well incorporated.
Combine drained and rinsed black beans, juice from one lime, and ground cumin in a medium bowl. Mash together using a fork until only small chunks of black bean remain.
Place pita breads on a baking sheet, top with shredded cheese then bake for about 10 minutes, until golden brown and cheese is melted.
In a small bowl, whisk together sour cream with the remaining lime’s juice plus a healthy pinch of salt and pepper until smooth.
ASSEMBLE: On each toasted and cheese covered pita, spread a scoop (~1/3 cup) of mashed butternut squash, a scoop (~1/4 cup) of mashed black beans, a scoop of ground beef, and a few slices of avocado. Top with a drizzle with the lime sour cream then garnish with cilantro!