Step 1Heat the oven to 300 degrees. Spread the pecans in a cake pan and toast them until lightly browned, 10 to 12 minutes. Cool, then coarsely chop the nuts. Set aside.
Step 2Wash the spinach well in several changes of cold water. Drain the spinach and immediately transfer the damp leaves to a large pot set over high heat. Cover and cook until the leaves are just wilted, 3 to 4 minutes. Strain through a colander and let stand until the spinach is cool enough to handle. Squeeze the spinach first with your hands to extract most of the moisture, then in a couple of layers of paper towels to dry the leaves completely. Chop very fine and set aside.
Step 3In a saute pan, fry the bacon over medium-high heat until crisp, about 12 to 15 minutes. Drain on paper towels, then cut each slice crosswise into half-inch pieces. Set aside.
Step 4In a mixing bowl, combine the sour cream, cream cheese and mayonnaise, and mix with a wooden spoon until smooth. Add the spinach and jalapenos and mix well. Stir in the pecans and bacon. Add the Worcestershire sauce and salt and mix well. Taste and adjust the seasoning. Cover and refrigerate the dip for at least 1 hour. Bring it to room temperature before serving.