Set the grated zucchini at 70°F room temperature and toss it with 1 teaspoon kosher salt. Leave it for 10 minutes. Then gather the shreds in a clean towel and twist firmly over the sink for 60 to 90 seconds. Reopen the towel once and move the wetter center shreds toward the outside before twisting again. The pile should shrink by nearly half and feel compact rather than slippery. You'll see only a few drops when you squeeze the final handful. Stop once the shreds hold together without releasing a stream. Skip this window and the batter stays watery, so the patties spread and steam. Squeezing removes free water so the fritters crisp instead of steaming.

Keep the whole-milk Greek yogurt at 40°F. Add lemon juice, one grated garlic clove, 1/4 teaspoon kosher salt and half the fresh flat-leaf parsley. Whisk for 30 seconds. Scrape the sides once, then chill the sauce at 40°F for 15 minutes. Stir only until the surface turns smooth and no lemon streaks remain. The sauce should look thick and glossy, with tiny green flat-leaf parsley flecks suspended throughout. You'll smell the lemon first and then the garlic. Taste after the full 15 minutes because the salt needs time to dissolve. Serve it sooner and the garlic tastes sharp while the texture feels loose. Chilling firms the yogurt so it clings instead of running. Preheat the oven to 350°F now so it's fully hot by the time the pan goes in.

Let the squeezed zucchini and egg sit at 70°F for 5 minutes. Then combine them with extra-sharp cheddar, all-purpose flour, baking powder and scallions. Add one grated garlic clove, fresh thyme, ground black pepper and the remaining salt. Fold with a rubber spatula in eight slow J-shaped strokes. Scrape the bottom once and rest the batter for exactly 5 minutes. The mixture should mound on the spatula and show separate green shreds with cheddar threads between them. It shouldn't pour or leave a puddle. (I doubled the flour in my first batch, the centers turned bready and dull.) Add more flour too quickly and the fritters lose their tender middle. A short rest hydrates the flour without building excess gluten.

Heat the refined avocado oil to 350°F over medium heat, about 5 on a 10-dial. Work in two batches. Scoop four loose 1/4-cup portions into the skillet and press each to 2 1/2 inches wide. Fry for 3 to 4 minutes without moving them, while leaving about 1 inch around each irregular patty. Cheesy Zucchini Fritters should hiss steadily and develop pale-gold rims by minute 3. Look for bubbles slowing around each edge and a dry-looking top surface. If the oil smokes, lower the heat at once. Move them before the crust forms and the patties tear across the skillet. Steady 350°F heat sets the egg before the cheddar can scorch.

Keep the avocado oil near 350°F and slide a thin spatula fully under each patty. Flip all four once, then shift darker pieces toward the cooler outer edge. Fry the second side for 2 to 3 minutes. Transfer them to a warm plate. Then cook the remaining four with the same timing and remove each at 160°F. The undersides should turn deep golden with darker cheddar freckles and crisp uneven rims. You'll hear the sizzle soften as surface moisture leaves. Go past 3 minutes after flipping and the exposed cheese can taste bitter. If one center still looks wet, give that fritter another 30 seconds. Reaching 160°F sets the egg while preserving the moist zucchini strands.

Let the fritters rest for 2 minutes on a warm 140°F holding plate. Then arrange two fritters per serving with slight overlap. Spoon 3 tablespoons of the chilled yogurt sauce into a small white ramekin. Scatter the remaining fresh flat-leaf parsley over the sauce and fritters, but keep the crisp rims visible. Serve within 5 minutes. The crust should stay crackly while the center looks tender and threaded with melted cheddar. Break one fritter open and you'll see moist green shreds without raw flour. Wait longer than 10 minutes and trapped steam softens the base. The cool sauce should hold a spoon mark instead of pooling. Brief resting lets steam escape before it can soften the crust.