Place 1 cup of sliced strawberries and ¼ cup of granulated sugar in a small saucepan. Use a masher or fork to break down the strawberries into a pulp.

Then heat the mixture over medium-low heat for a couple minutes while stirring frequently.

In a small bowl, combine 2 tablespoon water and 1 tablespoon cornstarch to make a cornstarch slurry. Pour into the strawberry mixture and continue to cook it until it becomes thick like jam. This usually takes about 5 minutes.

Pour the mixture into a bowl and place in the fridge uncovered to cool.

Preheat the oven to 350 F / 175 C and line two large baking sheets with silicone baking mats or parchment paper. Set aside.

In a large bowl or the bowl of a stand mixer, beat 1 cup butter and 1 cup granulated sugar and mix on a medium-high speed for a couple of minutes, until the mixture becomes lighter in color.

Then mix in 3 tablespoon of strawberry reduction, 1 large egg, 1 large egg yolk, 1 teaspoon vanilla extract, and a small drop of red gel food coloring (optional) on a medium speed until fully incorporated.

Add 2 ½ cups flour, 2 teaspoon baking powder, and 1 teaspoon fine salt, and mix on low speed until it is JUST incorporated.

Scoop 2 tablespoon of strawberry reduction to the top of the dough, then use a butter knife to gently marble the jam into the top of the dough.

Add ¼ cup of granulated sugar to a shallow dish. Use a 3-tbsp cookie scoop to scoop the dough into balls and roll them in sugar until they're evenly coated.

Place the cookies about 3 inches apart on the prepared baking sheets.

Bake for 10-12 minutes, or until the edges of the cookies are set but the centers are still a bit soft.

Cool for 15 minutes on the pan, then move the cookies to a wire rack to finish cooling.

If you want to spread any strawberry reduction on top of the cookies, do it right before you eat them.