Preheat your oven to 350°F (175°C). Generously grease and flour a 9x13-inch baking pan or a 10-inch Bundt pan. Consider lining the bottom with parchment paper if using a rectangular pan for easier removal.
Core and dice the apples into 1/2-inch pieces (no need to peel unless preferred). If not using immediately, toss with 1 tablespoon of lemon juice to prevent browning.
In a medium bowl, whisk together the flour, baking soda, salt, and cinnamon until evenly distributed.
In a large bowl, beat together the sugar and oil until well combined. Add eggs one at a time, beating well after each addition. Stir in vanilla extract until the mixture is smooth.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Avoid overmixing to prevent a tough cake.
Gently fold in the diced apples and chopped nuts until evenly distributed throughout the batter.
Pour the batter into your prepared pan, smoothing the top with a spatula. Bake for 50-55 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
While the cake bakes, prepare the glaze. Combine brown sugar, butter, and milk in a small saucepan. Bring to a boil over medium heat, stirring constantly. Boil for 1 minute, then remove from heat and stir in vanilla extract and salt.
When the cake is done, remove it from the oven and immediately poke the top all over with a fork or skewer. Pour the warm glaze evenly over the hot cake, allowing it to seep into the holes.
Allow the cake to cool in the pan for at least 30 minutes before serving to let the glaze fully penetrate and the cake structure to set.