Strawberry Jam:Make your strawberry jam ahead of time to allow time for cooling and setting before filling. Can be made days in advance. Combine all ingredients into a heavy-bottomed saucepan.
1 pound strawberries, 396 g granulated sugar, 2 tablespoons lemon juice
Simmer over medium-low heat until sugar is melted and jam is reduced down, stirring often, until jam reaches 220°F, approximately 30-45 minutes. Be sure to scrape the bottom and sides well to avoid burning.
You may need to skim surface of the jam to remove any foam as necessary.
To test if jam is set, place a metal spoon in the freezer for several minutes. Once chilled, drip a small amount of jam on the spoon. If the jam does not run when touched, it is ready to go..
Allow to chill for several hours before use.
Donuts:In a large mixing bowl, whisk together flour, sugar, salt, and yeast. 240 g all-purpose flour, 50 g granulated sugar, 1/2 teaspoon salt, 7 g active dry yeast
Combine milk and butter in a small saucepan. Heat on low until the butter melts and the milk reaches 110°F. Remove from heat.
2/3 cup whole milk, 3 tablespoons unsalted butter
Add egg and vanilla to milk mixture and pour into the dry ingredients. Mix until well combined and no dry flour remains.
2 egg yolks, 1 teaspoon vanilla
Cover with a clean towel and allow to rest for 10 minutes to develop the gluten.
Transfer the dough to a well floured surface and begin to knead. Dough will be quite sticky, but resist adding too much flour to avoid a tough donut. A plastic bench scraper is a great helper to lift and pick up the dough from the surface as you knead.
Continue kneading until the dough is smooth and springs back with poked, approximately 10-15 minutes, adding only as much flour as necessary.
Form dough into a ball and place in a clean bowl, cover with the towel and allow to proof in a warm, dry spot for about 1 hour, until dough has doubled in size.
Transfer dough to a lightly floured surface, and roll out 1/2" thickness. Cut 2.5" circles and place on a parchment lined baking sheet. Gather scraps and reroll only once for the best results.
Preheat oven to 375ºF.
Cover baking tray with towel and allow to proof for 1 hour before baking, letting the donuts proof to about 50% larger in size.
Bake for 10-12 minutes until donuts are golden brown.
While baking, melt 1.5 tablespoons of butter. Prepare cardamom sugar by mixing sugar and cardamom in separate bowl.
Immediately after removing from oven, brush warm donuts with melted butter and coat with cardamom sugar.
1 1/2 tablespoons unsalted butter, 100 g granulated sugar, 1 1/2 teaspoons cardamom
Once cooled completely, fill an icing bag with a round tip with strawberry jam. Poke a small hole in the side of the donuts and fill with jam.