Preheat a smoker to 250°F. Lightly grease the wells of a 12-cup muffin pan.
In a large bowl, combine the ground beef, egg, almond flour, 1/4 cup of the cheddar, 1 tablespoon of the sugar-free ketchup, chopped onion, smoked paprika, garlic powder, salt, and black pepper. Mix gently until just combined.
Divide the meat mixture among 8 muffin-pan wells. Press it in lightly, leaving the tops rounded rather than packing the mixture firmly.
Set the pan in the smoker and cook until the centers of the meatloaf muffins reach 160°F, about 1 to 1 1/2 hours. Spoon the remaining ketchup over the tops and sprinkle on the remaining cheddar during the last 10 minutes of cooking.
While the muffins smoke, steam the cauliflower florets until very tender, about 12 to 15 minutes. Drain well, then transfer them to a bowl. Add the butter and heavy cream and mash until smooth. Season with additional salt and pepper only if desired.
Remove the meatloaf muffins from the smoker and let them rest for 5 minutes. Serve two muffins per person over a portion of cauliflower mash.