Prep your pan and oven. Heat the oven to 350°F (175°C).
Line a 12-cup muffin tin with liners or lightly grease it.
Whisk the dry ingredients. In a large bowl, whisk flour, baking powder, baking soda, salt, and poppy seeds until well combined.
Mix the wet ingredients. In a separate bowl, whisk yogurt, oil, honey (or maple), eggs, lemon zest, lemon juice, and vanilla until smooth.
Bring it together. Pour the wet mixture into the dry ingredients. Stir gently with a spatula until just combined. If the batter seems very thick, fold in 2–3 tablespoons of milk to loosen.
Do not overmix.
Fill the tin. Divide the batter evenly among the muffin cups, filling each about 3/4 full.
Bake. Bake for 16–20 minutes, or until the tops spring back lightly and a toothpick comes out clean or with a few moist crumbs.
Cool. Let the muffins cool in the pan for 5 minutes, then move them to a wire rack to cool completely.
Optional glaze. Whisk powdered sugar with lemon juice until smooth and drizzle over cooled muffins. For a lighter touch, brush a little lemon juice mixed with a teaspoon of honey over the warm tops instead.