Preheat the oven to 400 degrees. Coat a muffin tray with cooking spray.
Rub the sugar with the chopped lemon zest together in a bowl with your fingertips until the sugar is moist and the lemon fragrance strong. Mix the flour, baking powder, baking soda, and salt together until well combined.
Beat the sour cream, lemon juice, eggs, vanilla extract, softened butter, and lemon sugar together in a bowl with a mixer until creamy and smooth. Slowly combine the flour mixture with the sour cream mixture. Add the poppy seeds and mix well. Add most of the strawberries and gently mix until well combined. Scoop the batter evenly into the muffin cups in the tray. Sprinkle the tops of the muffins evenly with the remaining diced strawberries.
Place into the oven and cook for 16-18 minutes, or until a tester inserted in the center comes out clean. Let the muffins cool on a rack before serving. Enjoy.