Prepare the Donut Batter:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease a donut pan with non-stick spray or butter.
2. Mix the Dry Ingredients: In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt.
3. Combine Wet Ingredients: In a separate bowl, whisk the melted butter, eggs, vanilla extract, and buttermilk until smooth.
4. Combine Wet and Dry Mixtures: Gradually fold the wet mixture into the dry ingredients. Stir gently until just combined, being careful not to overmix.
5. Fold in Raspberries: Gently fold the raspberries into the batter, ensuring they are evenly distributed but not crushed.

Fill the Donut Pan:

6. Pipe or Spoon Batter: Transfer the batter into a piping bag or use a spoon to fill the donut cavities about ¾ full.
7. Bake the Donuts: Bake for 12-15 minutes or until a toothpick inserted into the center comes out clean.
8. Cool Completely: Allow the donuts to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.

Prepare the Raspberry Glaze:

9. Blend and Strain Raspberries: Blend the raspberries and strain them through a fine-mesh sieve to remove seeds.
10. Mix the Glaze: In a bowl, whisk together the powdered sugar, raspberry puree, lemon juice, and milk if needed for thinning. The glaze should be smooth but thick enough to coat the donuts.

Glaze the Donuts:

11. Dip the Donuts: Once the donuts are fully cooled, dip the tops into the glaze and place them back on the wire rack.
12. Set the Glaze: Let the glaze set for 10-15 minutes before serving.