Preheat the oven to 425 degrees.\nToss potatoes with 2 Tbsp olive oil and ½ tsp each Belize spice and salt. Place in an even layer on a rimmed baking sheet and roast until tender, about 20-25 minute. \nMeanwhile, whisk together 1 Tbsp olive oil, honey, garlic, zest of 1 lemon, juice of half of a lemon (reserving the other half), remaining 3 tsp Belize spice and 1 tsp salt. Rub marinade evenly into both sides of each salmon filet until well coated. Slice the remaining whole lemon into thin rounds, about ⅛-inch thick.\nRemove potatoes from the oven and place the salmon, lemon rounds and shallots in an even layer on the baking sheet alongside the potatoes. Continue roasting for about 10-15 minutes more, until the salmon is cooked through to desired doneness and potatoes are beginning to brown. If desired, increase your oven temperature to broil and broil on the upper oven rack for 2-3 minutes, allowing the salmon and potatoes to crisp up. Note: every broiler is different so make sure to watch your dish carefully. \nMeanwhile, add the avocado, mayonnaise, basil, juice of remaining half lemon and a pinch of salt to the bowl of a food processor or blender. Blend until smooth and creamy, adding a few drops of water, if necessary, until sauce reaches desired consistency. Season to taste with salt. \nDivide salmon, shallots and potatoes among serving plates. Top with avocado mayo and fresh basil leaves. Dig in!