Make the Strawberry Sugar Dust. Place granulated sugar and freeze-dried strawberries in food processor
Process until the mixture is bright pink and the freeze-dried berries are pulverized
Make the sponge for the doughnuts and let it sit for 15 minutes. The sponge should rise and have lots of bubbles
While the sponge is sitting, add the other dry ingredients and remaining sugar to the flour and whisk to thoroughly combine
Add the eggs, remaining milk and yeast to the sponge and mix on low until just combined.
Add the flour one cup at a time and continue to mix on low until all the flour is incorporated
Switch to the dough hook and beat on medium speed for 6-8 minutes until the dough pulls away from the sides of the bowl
Scrape the dough onto a clean work surface and knead for 30 seconds until the dough is smooth and doesn't stick to your hands.
Place the dough on a lightly floured baking sheet and let it rise in a warm area until the dough doubles in size
Divide the risen dough into 15 pieces that weigh about 80 grams each
Shape the dough pieces into balls, place 3-inches apart on a parchment paper sprayed with non stick cooking spray
Fry the doughnuts 1 minute on each side and cool on rack place over a sheet pan
Strawberry Mascarpone Filling - Combine the sugar and mascarpone in a medium bowl. Beat the mixture just until blended
Add the heavy cream and beat until soft peaks form and the beaters leave visible marks in cream.
Add the strawberry jam and mix on low speed just until the strawberry jam is incorporated.
Use a paring knife to get a small slit into the side of the doughnut and pipe the mascarpone cream into the doughnut.
The doughnuts should be eaten right away or refrigerated for up to 2 days.