• Make the Topping.
• Add the avocado oil to a large non-stick skillet and heat to medium-high. Add the onions and sprinkle liberally with sea salt. Cover the skillet and cook, stirring occasionally, until the onions turn translucent and have softened. Remove the cover from the skillet and reduce the heat to medium or medium-low. Continue cooking, stirring occasionally, until the onions are brown and caramelized, about 50 to 60 minutes. 
• Remove caramelized onions from the heat and stir in the almond flour. Set aside until ready to use.

Pre-Cook the Green Beans:

• Heat a large pot of water on the stove top and bring it to a full boil. While the water is heating up, trim the ends off the green beans and chop them into 2-inch pieces. Transfer the green beans to the pot of boiling water and cook until softened, but still al dente, about 8 to 10 minutes. Immediately drain the beans into a colander and set aside until ready to use.

Make the Sauce:

• Cook the bacon over medium-high heat in a large skillet or thick-bottomed pot until crispy, about 5 minutes. Transfer the bacon to a cutting board and leave the drippings in the skillet. 
• Add the chopped mushrooms to the skillet and cook, stirring occasionally, until mushrooms have turned golden-brown and are much smaller than they were when raw, about 5 to 8 minutes. 
• Add the garlic and continue cooking for another 2 minutes. 
• Add the coconut milk, flour, and sea salt and bring the sauce to a full boil, whisking well until the flour clumps are out. Stir in the sun-dried tomatoes and kalamata olives. If adding parmesan cheese, do so now. Continue cooking the sauce until it has thickened to a consistency similar to gravy and pulls away from the skillet when stirred, about 5 to 8 minutes.

Compile the Casserole:

• Preheat the oven to 375 degrees Fahrenheit.
• Transfer the cooked and drained green beans to a large (13” x 9”) casserole dish. Drizzle with avocado oil and sea salt and toss everything together until all of the beans are coated with oil.
• Pour the creamy Mediterranean sauce into the casserole dish and stir well until the beans are well-coated in sauce.
• Evenly distribute the caramelized onions over the green beans. Transfer the casserole dish to the pre-heated oven and bake for 20 to 25 minutes, until the casserole is fragrant and bubbly.
• Chop the bacon and sprinkle the crumbles over the casserole.
• Serve with alongside your main dish and enjoy!