Make sure broccoli, cauliflower, and spinach are well-drained. Press gently with paper towels to remove excess water.

In a large bowl, combine broccoli, riced cauliflower, spinach, eggs, almond flour, pepper, salt, paprika, and lemon juice (if using). Mix until everything is evenly coated.

Grease a 9×13-inch baking dish (or 8×8 for thicker slices) with a light brush of olive oil. Spread mixture evenly.

Sprinkle with extra paprika or sesame seeds for color.

Bake at 375 degrees Fahrenheit (190 degrees Celsius) for 40–50 minutes, until set in the middle and edges are golden brown.

Let rest 10 minutes before slicing so it holds together.