Heat the oven to 350°F. Spray an 8 inch square baking pan with nonstick spray; dust with flour. Set aside.
Drain the pineapple in a sieve set over a bowl, pressing on the solids. Reserve the drained pineapple and pineapple juice.
In a large mixing bowl, combine the pineapple, pecans, and raisins. Add sugar, eggs, and oil. Stir to combine. Add flour, baking powder, baking soda, salt, cinnamon, allspice and nutmeg. Add carrots and stir to combine. Transfer to the prepared pan.
Bake until a wooden pick inserted in the center of each layer comes out clean and the sides start to pull away from the edges of the pans, 35 to 40 minutes. Remove to a rack to cool. Brush the cake with the reserved pineapple juice.
Frosting: Using a hand held mixer combine the cream cheese, vanilla and salt. With the mixer at low speed, add the confectioners’ sugar. Blend until smooth and consistent.
Once the cake has cooled completely. Top with the frosting. Garnish the top with the pecan halves. To serve, slice with a serrated knife. Store in an airtight container in the refrigerator for up to 3 days.