1. Preheat the oven to 350°F (175°C). Grease a 9x9-inch baking dish with cooking spray or a small amount of butter.

2. In a medium mixing bowl, combine the sweetened condensed milk and eggs. Whisk until smooth. Add the cinnamon, ginger, nutmeg, and salt and stir until evenly combined.

3. In a separate bowl, whisk together the flour, granulated sugar, and baking powder.

4. Gradually add the dry ingredients to the wet mixture. Stir gently until just combined; do not overmix.

5. Fold in the melted butter. If using pecans, stir in about 1/2 cup chopped pecans, reserving a small amount for the top if desired.

6. Pour the batter into the prepared baking dish and spread evenly. Sprinkle any reserved pecans over the top.

7. Bake for 30–35 minutes, or until the top is golden brown and a toothpick inserted near the center comes out clean or with a few moist crumbs.

8. Remove from the oven and cool for 10–15 minutes before serving. Serve warm, with vanilla ice cream or whipped cream if desired.