You can make the dip the day before and store it in the fridge until you're ready.
Thaw and drain the spinach in a colander. Squeeze out the excess liquid. Chop.
Drain your artichokes and gently squeeze each artichoke heart to remove the excess liquid. Chop.
Mix together the chopped spinach, artichoke heart and minced garlic.
Add remaining ingredients and mix well.
Place all ingredients in a stand mixer bowl. Mix with the paddle attachment until thoroughly combined.
Change from the paddle attachment to the dough hook and mix on medium speed for about 8 minutes or until dough comes together, becomes smooth, elastic and stretches easily without breaking.
Place dough in a greased bowl and turn dough around to grease all sides. Cover bowl with a damp tea towel.
Place covered bowl in a cold oven with the light on to rise. Wait for the dough to double in size. This takes about an hour.
Once doubled, remove dough from the oven and punch it down to remove the large air pockets.
Turn dough out onto a floured surface and divide into two equal portions. Form each portion into a ball.
Roll out first ball until it is about 2 inches wider than a dinner plate. Transfer to a piece of parchment paper for easier handling.
Mark a circle in the middle of the dough using a cereal bowl.
Fill the center circle with dip.
Create a ring of dip around the center circle leaving 1 inch on the outside to allow the dough to seal.
Roll out your second ball of dough so that it is slightly larger than the first. Place over first dough circle and dip.
Using the same cereal bowl, press down over the center pile of dip. Then press the dough together between the ring and the center pile. Then press down around the edges of the circle.
Seal edges shut using a fork. Press the tines around the circle edge to press the dough layers together. Trim the dough to a neat circle.
Cut the dough from the edge to within 1/2 inch of the center dip pile at 12, 3, 6 and 9 o'clock.
Cut each section again in the middle to form 8 sections.
Cut each section again in the middle to form 16 sections.
Twist each section 90 degrees and press down on the tips of the petals.
Beat together the egg yolk and milk to form an egg wash. Brush over the sunflower.
Sprinkle poppy seeds and sunflower seeds on the center of the sunflower.
Bake at 350 degrees for 40 minutes or until the dough in the center is done.