Preheat oven to 375 degrees F.
Scrub and dry sweet potatoes. Cut them in half horizontally and place them skin-side up on a baking sheet. Place in preheated oven for 30 minutes.
While sweet potatoes bake, finely dice the onion.
In a large bowl, add ground beef, diced onion, eggs, cassava flour, basil, garlic and salt and pepper. Use clean hands to mix until just combined.
Grease muffin tins generously with avocado oil.
Divide the meat into muffins tins - filling to the top of each cup.
Bake in middle rack of oven for 30-35 minutes or until the insides are no longer pink.
Once sweet potatoes finish baking, allow them to cool on the counter for a few minutes. Once cooled, use a spoon to scoop out the insides and place in a medium sized bowl. Add ½ teaspoon of salt. Smash sweet potatoes with a fork until smooth.
Spoon sweet potato topping onto meatloaf muffins or add sweet potato filling to a sandwich bag and snip off the corner to pipe filling onto muffins.
Drizzle with Whole 30 compliant barbeque sauce and garnish with freshly chopped parsley if desired.