Preheat your oven to 325°F (160°C). Grease and flour a 9x5 inch loaf pan thoroughly, ensuring all crevices are coated. Alternatively, you can line it with parchment paper, leaving an overhang on the sides for easy removal.

In a medium bowl, whisk together the 3 cups of all-purpose flour, baking powder, and salt. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer), cream together the softened butter and granulated sugar on medium-high speed until light, fluffy, and pale in color, about 5-7 minutes. Scrape down the sides of the bowl as needed.

Add the eggs one at a time, beating well after each addition until fully incorporated. Do not overmix.

In a small separate bowl, whisk together the sour cream and vanilla extract.

With the mixer on low speed, gradually add the dry ingredients to the wet ingredients in three additions, alternating with the sour cream mixture, beginning and ending with the dry ingredients. Mix until just combined after each addition; do not overmix, as this can result in a tough cake.

In a small bowl, toss the diced fresh strawberries with 1 tablespoon of all-purpose flour. This step helps prevent the strawberries from sinking to the bottom of the cake during baking.

Gently fold the floured strawberries into the cake batter using a rubber spatula until evenly distributed.

Pour the batter into the prepared loaf pan and spread evenly. Gently tap the pan on the counter a couple of times to release any air bubbles.

Bake for 65-75 minutes, or until a wooden skewer or toothpick inserted into the center of the cake comes out clean. If the top of the cake starts to brown too quickly, you can loosely tent it with aluminum foil.

Once baked, remove the cake from the oven and let it cool in the pan on a wire rack for 15-20 minutes before inverting it onto the wire rack to cool completely. The cake must be completely cool before glazing.

While the cake cools, prepare the strawberry puree for the glaze. Process or blend the 1/4 cup fresh strawberries until smooth. You can strain it through a fine-mesh sieve if you prefer a completely seedless glaze.

In a small bowl, whisk together the sifted powdered sugar, strawberry puree, and optional lemon juice until smooth and lump-free. The consistency should be thick but pourable. If too thick, add a tiny bit more strawberry puree or milk; if too thin, add a bit more powdered sugar.

Once the cake is completely cool, drizzle the strawberry glaze over the top, allowing it to drip down the sides. Let the glaze set for about 15-30 minutes before slicing and serving.