Clean and drain strawberries. Cut the tops off and hull out the middle. Cut fresh strawberries into pieces by cutting them into quarters and then cut the quarters in half, giving you 8 pieces per strawberry. Lay a paper towel on a plate and add the strawberry pieces cut side down on the paper towel. Leave the strawberries on the towel for 2 hours; this will help to absorb the liquid from the strawberries.
In a bowl, weigh or measure the flour, salt, and baking powder and set aside. I run a whisk through the dry ingredients to blend. Measure or weigh the sugar and add it to the mixer bowl.
With a hand-held or stand mixer, incorporate the sugar, butter, and mascarpone on medium speed for 2 to 3 minutes. Next, add the vanilla extract and one egg, ensuring the first egg is completely incorporated before adding the second. Next, scrape down the sides and across the bottom, then gradually add the flour mixture on a low mixer speed.
I transfer the cookie dough to a bowl with a wide mouth and fairly low sides. I find this bowl type easier to fold the strawberries into the cookie dough, but you can certainly use the mixer bowl. Fold in the cut-up strawberries and mix them through the dough. Cover lightly with plastic wrap and refrigerate for 2 hours.
Preheat oven to 375°F (190°C), line two baking sheet pans with parchment paper, and set aside. Add 9 scoops to a prepared sheet pan and bake for 12-14 minutes using a medium cookie scoop. When you see a little brown around the bottom edges, pull them out of the oven. Leave them on the pan for about a couple of minutes, then move them to a cooling rack.