Preheat oven to 350 degrees F (175 degrees C). Grease 10 mini cake molds.

Drain pineapple rings, reserving 1/4 cup juice.

Combine flour and baking powder in a small bowl.

Combine 3/4 cup melted butter and white sugar in a large bowl. Beat with an electric mixer on medium speed until well blended, about 3 minutes. Add eggs one at a time. Mix in reserved 1/4 cup pineapple juice, 1/2 cup coconut cream, milk, 1 tablespoon coconut extract, and vanilla extract. Add flour mixture gradually, mixing until batter is smooth.

Mix brown sugar and 1/3 cup melted butter together in a bowl until smooth. Spoon into the bottom of the cake molds. Place 1 pineapple ring in each mold. Place 1 maraschino cherry in the center of each ring.

Divide batter among cake molds using an ice cream scoop.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, 20 to 22 minutes. Cool to room temperature, about 20 minutes. Run a knife around the rims to loosen cakes; invert gently onto a plate.

Pour heavy cream into a chilled metal bowl. Add cream of tartar. Beat with an electric mixer until almost holding peaks. Add confectioners' sugar gradually, continuing to beat until soft peaks form. Fold in 1/4 pineapple juice, 3 tablespoons coconut cream, and 1 tablespoon coconut extract.

Serve whipped cream alongside cakes.