Step 1

In a small skillet, heat 1/4 cup of the olive oil. Add the panko and toast over moderate heat, stirring, until golden, about 5 minutes. Stir in the parsley and season with salt and pepper. Transfer to a paper towel–lined plate to drain; let cool.

Step 2

Meanwhile, in a pot of salted boiling water, cook the spaghetti until al dente. Drain well, reserving 1 cup of the pasta water.

Step 3

In a large pot, combine the remaining 1/2 cup of oil with the garlic and cook over low heat, stirring occasionally, until the garlic is fragrant and light golden, 7 to 8 minutes. In batches, add the greens and cook, tossing, until wilted, about 3 minutes. Season with salt and pepper. Add the pasta, 1/2 cup of the reserved pasta water and the lemon juice; cook, stirring, until a sauce forms, 2 minutes. Divide the pasta among bowls and top with the panko.