1. Spread the refried beans on the bottom of your serving dish
2. In a bowl, mash the avocados and mix in the salt, lemon juice, horseradish, and sour cream
3. Spread the avocado mixture on top of the beans
4. In another bowl, mix the remaining cup of sour cream, mayonnaise, and taco seasoning
5. Spread that on top of the avocado mixture