Step 1Heat the oven to 375 degrees. Butter a 12-cup muffin pan or line the cups with paper liners.
Step 2Place 1 cup of the sugar, the buttermilk, oil, egg, zest and poppy seeds in a large bowl. Use a wooden spoon to mix well. Add the flour, baking soda, salt and lemon extract. Stir until just combined; do not overmix. Spoon the batter into the prepared cups.
Step 3Bake the muffins until lightly browned and a toothpick inserted into the center of one comes out clean, about 20 minutes. Let cool in the pan for 5 minutes.
Step 4Combine the 2 tablespoons of sugar and the lemon juice in a small bowl and microwave on high for 1 minute. Dip the tops of the muffins in the glaze while still hot. Let the muffins rest at least 20 minutes before serving.