Butter a 7-inch springform pan and set it aside.

Make the topping: In a small saucepan over medium-low heat, melt 4 tablespoons unsalted butter. Add 2 tablespoons pineapple juice, 1 teaspoon lime juice, 1/2 teaspoon cinnamon, 1/4 teaspoon nutmeg, and 1/2 cup brown sugar. Stir until the sugar dissolves and the mixture is smooth and slightly simmering. Remove from heat and stir in 1 teaspoon coconut extract.

Pour the warm topping evenly into the bottom of the prepared 7-inch springform pan.

Arrange the pineapple and cherries: Place one whole pineapple slice in the center of the pan and put one maraschino cherry into the center of that slice. Cut the remaining pineapple slices in half and arrange them around the center slice (and up the sides of the pan if needed) so the bottom of the pan is covered. Place one maraschino cherry in the center of each pineapple slice or piece as you arrange them.

Prepare the batter: In a large bowl using a hand mixer, beat 1/4 cup unsalted butter (softened to room temperature), 1/3 cup sugar, and 1/2 cup dark brown sugar (packed) on medium speed until light and fluffy (about 2–3 minutes).

With the mixer on low, beat in 1 egg and 1 teaspoon coconut extract until combined.

Add 1 1/2 cups flour, 2 teaspoons baking powder, and 1/4 teaspoon salt to the bowl. Pour in 1 cup coconut milk. Beat on low/medium until the batter is just combined, scraping the bottom and sides of the bowl with a spatula to ensure there are no dry pockets.

Pour the batter evenly over the arranged pineapple and cherries in the springform pan and smooth the top with a spatula.

Cover the pan loosely with foil.

Prepare the Instant Pot: Pour 1 cup of water into the Instant Pot insert and place a trivet inside.

Lower the covered springform pan onto the trivet in the Instant Pot.

Seal the Instant Pot lid, set to High Pressure, and cook for 55 minutes.

When the cook time ends, allow a 30-minute natural pressure release (do not open the valve during this time).

After the 30-minute natural release, carefully release any remaining pressure manually, then open the lid and use oven mitts to remove the springform pan from the Instant Pot.

Let the cake cool in the pan for 10–15 minutes. Run a knife around the edge if needed, then place a serving plate over the pan, invert the cake onto the plate, and remove the springform ring.

Let the inverted cake cool an additional 10 minutes before slicing and serving.