In a medium bowl, mix together the flour, salt and yeast. Add the water and mix with a wooden spoon or your hands. It should be sticky, but not lumpy.
Cover with saran wrap and a towel in a warm place, allowing it to rise for 24 hours. Transfer to a floured surface and shape into ball. Use when ready.
Sauce
Add butter to small skillet over medium heat. Add garlic and cook for 30 seconds. Add flour and cook for about 1 minute, or until bubbly.
Slowly whisk in milk and chicken stock and cook for about 1 minute or until thickened. Add ¼ cup Parmesan cheese and and crushed red pepper flakes, stirring to combine. Remove from heat and set aside.
Pizza
Place pizza stone in oven 8" from the broiler element and preheat to 500°F. You want stone to be in oven for at least 30 minutes at 500°F.
Heat medium skillet with 1 tablespoon olive oil over medium-high heat. Season steak with salt and pepper and cook for 1-2 minutes on each side until cooked. Remove from skillet.
In same skillet over medium-high heat, add remaining olive oil. Add sliced peppers and onion and and cook for about 3 minutes.
Sprinkle pizza peel with cornmeal or flour. Use your hands to gently tug, pull and push the dough to the shape you want and place on pizza peel.
Spread a light layer of the sauce over the dough, leaving about 1 inch around the edges untouched. Spread the cooked steak, peppers and onion throughout the pizza. Top with the cheese.
Once stone is preheated, turn broiler to high. Transfer pizza to pizza stone and bake for 4-5 minutes or until top is bubbly and bottom is golden brown.