Preheat the oven to 350°F (175°C). Lightly grease a 6- or 12-cavity doughnut pan with butter or nonstick spray.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt until well combined.
In a separate bowl, whisk the eggs, milk, oil, yogurt, vanilla, and lemon zest until smooth and creamy.
Pour the wet ingredients into the dry ingredients. Stir gently with a spatula until just combined. Do not overmix; a few small lumps are fine.
Toss the chopped raspberries with 1 teaspoon of flour to help prevent sinking. Fold them gently into the batter.
Spoon or pipe the batter into the doughnut pan, filling each cavity about 2/3 full. A piping bag or zip-top bag with the corner cut off makes this easy.
Bake for 10–12 minutes, or until the doughnuts spring back when lightly touched and a tester comes out clean.
Let the doughnuts cool in the pan for 5 minutes, then transfer to a wire rack to cool completely before glazing.
Make the glaze: Place the white chocolate and butter in a heatproof bowl. Microwave in 15–20 second bursts, stirring between each, until melted and smooth. Stir in the vanilla, salt, and 2 tablespoons of cream. If too thick, add a little more cream until pourable but not runny.
Dip the cooled doughnuts into the glaze, letting the excess drip back into the bowl. Place on a rack and top with crushed freeze-dried raspberries or white chocolate curls while the glaze is still tacky.
Let the glaze set for about 15–20 minutes. Serve and enjoy.