Pre-heat the oven to 350 and line a sheet tray with aluminum foil. Spread the diced apple and walnuts in an even, single layer on the tray and let them toast in the oven for about 5 minutes. The apples should just be a little soft and the walnuts fragrant but not burnt. When they are done let the tray cool for a minute, then add the crumbled goat cheese to it to just warm it slightly without melting it. Add the mixture to a large salad bowl with the spinach and toss it all together well.

While the apple and walnuts toast up, quickly make the simple vinaigrette. Combine the balsamic, Dijon, shallot and salt together in a bowl and whisk them together well. Continue to whisk as you pour in the olive oil to bring the dressing together. This is an emulsion and after a while it will separate. That's ok, it just needs a good shake in a sealed bottle to bring it together again! Serve the salad immediately with the dressing and enjoy.