Preheat your oven to 350°F (175°C) and generously spray a standard 12-cup muffin tin with non-stick cooking spray, coating the sides and bottom of each cup. Set aside; repeat with a second tin if making the full batch.
Stir together the melted butter and brown sugar in a small bowl until smooth, then spoon about 1 tablespoon of the mixture into the bottom of each muffin cup, spreading it evenly with the back of the spoon.
Spoon about 1 tablespoon of well-drained crushed pineapple over the brown sugar layer in each cup and press lightly to flatten, then place one dry maraschino cherry in the center of each, pressing gently so it sits secure.
Beat the softened butter with an electric mixer on medium speed for 1 minute until creamy, then add both sugars and beat on medium-high for 2–3 minutes until light, fluffy, and increased in volume.
Add the egg and vanilla extract to the butter-sugar mixture and beat until fully incorporated, scraping down the bowl as needed — a slightly curdled appearance at this stage is normal.
In a separate medium bowl, whisk together the flour, baking soda, salt, and cinnamon until evenly combined and lump-free.
Add the dry ingredients to the wet ingredients all at once and mix on low speed just until no dry streaks remain — stop as soon as the dough comes together to keep cookies tender.
Scoop about 2 tablespoons of dough per cookie and place on top of the pineapple-cherry layer in each muffin cup, pressing gently to spread the dough to almost the edges of each cup.
Bake on the center rack for 12–14 minutes, until the tops are lightly golden and spring back when touched — edges should look set while centers may appear slightly soft.
Let cookies cool in the pan for exactly 5 minutes, then run a butter knife around each edge, place a large cutting board over the tin, and carefully flip the entire tin upside down to release the cookies topping-side up. Cool completely on a wire rack before serving.