Special equipment: Cheesecloth
For the blue cheese sauce: Whisk together the yogurt, mayonnaise, lemon juice, milk, Worcestershire and cayenne in a medium bowl until smooth. Gently stir in the blue cheese. Season with 1/2 teaspoon salt and pepper to taste. Refrigerate overnight or up to 3 days, covered, to let the flavors develop.
For the cauliflower tots: Position an oven rack at the top of the oven, and preheat to 450 degrees F. Set a cooling rack on a rimmed baking sheet.
Heat the oil in a large skillet over medium-high heat. Add the onion, and cook, stirring frequently, until browned and soft, about 5 minutes. Remove from the heat, and let cool in the skillet.
Remove and discard the outer leaves and core of the cauliflower. Separate the heads into large florets, and trim away most of the stems. Process half the florets in a food processor until very finely chopped, almost a paste. Transfer to a large bowl. Repeat with the remaining florets.
Lay out a large double layer of cheesecloth, and put the cauliflower paste in the middle. Gather up the sides into a bundle. Hold the bundle over the sink, and squeeze out as much of the liquid as you possibly can (there will be a fair amount). Put the remaining cauliflower back into the bowl (it should be fairly dry now).
Add the browned onion, almond meal, egg whites, hot sauce, 2 teaspoons salt and cayenne to the cauliflower, and work together with your hands until combined and the mixture holds together when squeezed.
Scoop out even tablespoonfuls of the cauliflower mixture. Roll each into a ball, shape into a squared-off tot shape and place on a baking sheet. (The tots can be covered loosely with plastic wrap and refrigerated up to overnight.)
Pulse the rice cereal in the food processor until finely ground, then transfer it to a small dish. Whisk the egg yolks with 1/4 cup water in a medium bowl. Line up the tots, egg wash, ground cereal and prepared baking sheet (with rack) on your work surface. Dip each tot in the egg wash, letting the excess liquid drip off, then roll in the cereal to fully coat and place on the baking sheet. (To avoid a mess, designate one hand for the dipping and retrieving in the egg and the other for rolling in the cereal.) Spray each tot all over with the cooking spray, turning as needed. (The unsprayed breaded tots can be frozen on a parchment-lined baking sheet until solid, about 2 hours, then transferred to a large freezer bag and frozen for up to 1 month.)
Bake the tots on the prepared baking sheet until golden brown outside and hot inside, 15 to 20 minutes. Let cool for a few minutes, then transfer to a serving platter. Shake some hot sauce on top. Serve with the blue cheese sauce. (If baking the tots from frozen, coat with cooking spray and bake for until golden brown outside and hot inside, 15 to 20 minutes.)
Copyright 2015 Television Food Network, G.P. All rights reserved.