Prep the pan: Heat oven to 375°F (190°C).
Line a 12-cup muffin tin with paper liners or grease lightly.
Zest and juice: Finely zest 2 lemons, then juice them. You’ll want about 2 tablespoons zest and 1/3 cup juice total. Set aside.
Mix dry ingredients: In a large bowl, whisk 2 cups all-purpose flour, 3/4 cup sugar, 2 teaspoons baking powder, 1/2 teaspoon baking soda, 1/2 teaspoon fine salt, and 2 tablespoons poppy seeds.
Combine wet ingredients: In a separate bowl, whisk 2 large eggs, 3/4 cup plain Greek yogurt, 1/2 cup neutral oil, 2 teaspoons vanilla extract, 2 tablespoons lemon zest, and 1/4 cup lemon juice.
Add 1–2 tablespoons milk only if the mixture feels very thick.
Bring it together: Pour the wet mixture into the dry. Use a spatula to fold gently until just combined. Do not overmix. A few small floury streaks are okay.
Portion the batter: Divide evenly among the muffin cups, filling each about 3/4 full.
For taller domes, let the filled pan rest 10 minutes before baking.
Bake: Bake 15–18 minutes, until the tops are set and lightly golden, and a toothpick comes out with a few moist crumbs. Avoid overbaking to keep them tender.
Cool: Let muffins cool in the pan 5 minutes, then transfer to a wire rack.
Optional lemon glaze: Whisk 1 cup powdered sugar with 2–3 tablespoons lemon juice until smooth and pourable. Drizzle over warm (not hot) muffins for a glossy, tangy finish.