Preheat the convection air oven to 325 F. If you don’t have convection air oven raise the temperature to 350 F and you’ll have to rotate the pan half way through the baking time. Butter and flour 8.5 x 4.5 x 3 inches loaf pan, then line it with parchment paper and set aside.
Combine cake flour with baking powder and salt, sift it three times and set aside (or, stir with a wire whisk until well combined).
In a small sauce pan, brown 2 tablespoons butter over medium heat to get nice amber color, remove the foam and set aside to cool.
Whisk eggs and vanilla, set aside.
Cream the butter on medium speed, slowly add sugar and continue mixing until smooth. Add heavy cream and mascarpone, and beat on medium speed to combine, then turn the mixer on low speed and gradually add dry ingredients alternately with eggs.
Add one tablespoon flour in chocolate chips and toss them to cover evenly. Toss diced strawberries with a handful flour to cover them completely.
Using a spatula, stir chocolate chips in the batter, then gently stir in strawberries and pour the batter into prepared pan, smooth the top and gently tap it onto working surface to remove the air bubbles.
With a butter knife, draw a line down the center of the cake and pour browned butter into the line.
Bake until the top of the cake is golden brown and a toothpick inserted in the center comes out clean (about 60 to 70 minutes). Cool the cake in the pan for 15 minutes, then remove from the pan, place on a rack, and cool completely.