Bring a large pot of salted water to a boil. Next put a bowl of ice water.
Add spinach in boiling water and blanch for 10-20 seconds. Put the spinach in a bowl of ice water for a few minutes. Strain and remove the excess moisture. Coarsely chop.
Heat 1 tablespoon oil in a large skillet over medium heat.
Add the chopped garlic. Cook, stirring, for about 30 seconds.
Stir artichokes. Cook for a couple of minutes.
When the artichokes begin to gain color, add the thyme and spinach leaves. Season with salt and pepper. Remove from heat.
Preheat the grill.
On 4 slices Put the artichokes and spinach. Add the bell pepper, cut into slices, and cheese. Cover with remaining 4 slices of bread.
Brush bread with oil on both sides and fry on the grill for 4-5 minutes.
Serve.