Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish or line it with parchment paper.
In a medium bowl, mix together the diced strawberries with 1 tablespoon of granulated sugar and set aside to macerate.
In a large mixing bowl, cream together the softened butter and remaining sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition. Mix in the vanilla extract.
In another bowl, whisk together the flour, baking powder, baking soda, cinnamon, and salt.
Gradually add the dry ingredients to the butter mixture alternately with the milk, starting and ending with the flour mixture. Mix until just combined; do not overmix.
Gently fold the macerated strawberries into the batter.
Pour the batter into the prepared baking dish and spread it evenly.
Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted in the center comes out clean.
Allow the cake to cool in the pan for about 10 minutes before transferring to a wire rack.
Once completely cool, dust with powdered sugar before serving if desired.
Notes
Cut into squares and garnish with fresh strawberries for an appealing finish.