In a small bowl, mix the spices together. Completely coat the beef with the spice mix. In a pan, heat the oil over medium-high heat and sear the beef on all sides until golden brown and crusted, about 2 minutes on each side.
Wrap the tenderloin in plastic wrap and place in the refrigerator until ready to slice.
For the aioli:
With the back of a knife, crush the garlic. Place in a bowl with 1 teaspoon salt and the Dijon mustard. Add the egg and whisk to blend. Slowly whisk in the oil, a little at a time, until all the oil is mixed in and the aioli emulsifies and becomes thick and creamy. Add the lemon juice and zest. If you need to thin the sauce, add water until you get the consistency you like. Season with salt and pepper. Keep refrigerated until ready to use. (Use within 24 hours.).
For the chips and capers:
Rinse the potato slices under cold water and put them in a large bowl with the salt. Rinsing the potatoes will ensure they don't change color and will remove some of the starch. Add cold water to cover and set aside. (The longer the potatoes stay in the water, the crispier they will be when you fry them.).
Drain the potatoes from the water and pat dry between paper towels. Dry off the capers with a paper towel and set aside.
Using a deep fryer, heat the oil to 350 degrees F. Working in small batches, fry the potato chips, stirring a few times, until golden, about 2 minutes. Transfer the potato chips to paper towels to drain excess oil. Sprinkle with salt and reserve.
Fry the capers until golden, 30 to 45 seconds. Reserve on paper towels to drain.
Take the beef out of the refrigerator. Using a very sharp knife, cut slices as thinly as you can.
Mix the baby spinach with the olive oil. Season with salt and pepper.
Plate the beef slices on individual plates, spoon the lemon aioli on the beef, garnish with the seasoned spianch, the potato chips, fried capers and chives.
Aioli is great on burgers, sandwiches, as a dip for vegetables, etc.
Consumption of raw or undercooked eggs may increase the risk of foodborne illness.