Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 9x13-inch baking pan.

Place chopped tomatoes in a bowl; sprinkle with 1 tablespoon salt. Set aside for 10 minutes. Transfer to a colander; rinse with cold water. Drain.

Meanwhile, beat sugar and butter together in a large bowl with an electric mixer until light and fluffy; beat in eggs, one at a time, beating well after each addition until creamy.

Combine flour, cinnamon, nutmeg, baking soda, and 1/4 teaspoon salt in a bowl; stir in raisins and walnuts. Stir flour mixture into egg mixture until well combined.

Stir drained tomatoes into batter until well combined. Transfer batter to the prepared baking pan.

Bake in the preheated oven until a toothpick inserted into center comes out clean, 40 to 45 minutes.