Line a large plate or baking sheet with parchment. In a medium bowl, combine cream cheese, confectioners' sugar, and lemon zest until smooth. Scoop into 12 small balls (about 1 ½ tsp. each) and place on prepared plate.

Freeze until solid, about 30 minutes.

Line 2 large baking sheets with parchment, then grease with cooking spray. In a small bowl, stir strawberries, lemon juice, and 1 Tbsp. granulated sugar until combined. Let sit 10 minutes, then drain.

In a medium bowl, whisk flour, baking powder, and salt.

In a large bowl, using a handheld mixer on medium-high speed, beat butter, brown sugar, and remaining ½ cup granulated sugar until light and fluffy. Beat in egg and vanilla, then fold in flour mixture until just combined. Gently fold in strawberries.

Using a medium cookie scoop, scoop heaping tablespoons of dough (about 24 balls) and flatten into pancake-like circles. Place frozen cream cheese filling balls on top of 12 pieces of dough. Place remaining dough on top of filling and pinch edges together. Gently roll into balls with your hands.

Arrange stuffed dough balls on prepared sheets, spacing about 2" apart. Sprinkle with sparkling sugar (if using). Freeze until solid, about 30 minutes.

Arrange a rack in center of oven; preheat to 350°. Bake cookies until set and just golden around edges, about 18 minutes.