Preheat the oven to 300 degrees F (150 degrees C). Lightly grease an 11x7-inch baking pan. Line with parchment paper, leaving an overhang over the edges.

Combine butter and sugar in a bowl; beat with an electric mixer until light and fluffy. Add egg yolks one at a time, beating well after each addition. Mix in vanilla extract.

Sift flour and baking powder together in a bowl. Fold into the creamed mixture until dough comes together. Press dough into the lined baking pan; prick all over with a fork.

Bake in the preheated oven until set, about 10 minutes. Spread raspberry jam thinly over the cake base.

Beat egg whites in a glass, metal, or ceramic bowl until soft peaks form. Add sugar 1 tablespoon at a time, continuing to beat until stiff, glossy peaks form. Gently fold in coconut and vanilla extract. Cover the jam layer with meringue.

Bake until the meringue topping takes on a soft pink or eggshell color, 20 to 25 minutes. Cool in the pan for 2 to 3 minutes, then carefully lift out using the parchment paper. Cool on a wire rack. Cut into squares.