Mix the dry ingredients: In a large bowl, whisk the flour, baking soda, and salt until evenly combined.
Mix the wet ingredients: In another large bowl, mix the egg and sugar until evenly combined. Whisk the oil, buttermilk, vanilla extract, and lemon zest until evenly mixed.
Gradually, add the wet ingredients to the dry ingredients, whisking as you pour just until there are no lumps as best as you can. Try not to overmix.
Toss most of the diced strawberries with flour (reserve about 3 tablespoons for later). Gently, fold in prepared strawberries into the batter.
Pour batter into the prepared pan. Top with the remaining diced strawberries, gently pushing them down into the batter but letting them still be visible. This will make the bread more beautiful.
Bake for about 55-60 minutes, or until a toothpick inserted in the middle comes out clean, and until golden brown. At 40 minutes into baking, cover with foil to prevent it from browning too much. Tip: don't open the oven too many times while baking or the bread will not rise properly.
Let cool slightly and slice. The strawberries inside will look a bit pale, which is normal.